1349 lines
110 KiB
Plaintext
1349 lines
110 KiB
Plaintext
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******************************************************************
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* *
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* DOS's coldstart routine *
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* *
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*----------------------------------------------------------------*
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* *
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* The DOS cold- and warmstart routines represent the focal *
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* points from which DOS begins processing information. It *
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* therefore seems logical that the novice should launch his trek *
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* into DOS from these routines. However, the cold- and warm- *
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* start routines are difficult to understand because: *
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* 1) Program execution bounces back and forth between DOS, *
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* BASIC and monitor ROM. *
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* 2) Both the cold- and warmstart routines are riddled with *
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* references to an obscure version of Applesoft that most *
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* people don't even realize exists. *
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* 3) The DOS coldstart routine uses part of the warmstart *
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* routine. In order to distinguish between these two *
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* execution patterns, it is important to pay close *
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* attention to the condition of the status register and *
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* several different flags. *
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* *
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* ABOUT PROGRAM EXECUTION AND THE I/O HOOKS. *
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* The interconnection between DOS, BASIC and monitor ROM is *
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* accomplished by DOS's control over the input (KSW: $36,$37) *
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* and output (CSW; $38,$39) hooks. (These hooks are collectively*
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* referred to as the I/O hooks, the KSW/CSW hooks or the *
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* keyboard/character switches.) In order to understand how DOS *
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* controls these hooks, lets first see what happens when DOS is *
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* NOT present: *
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* - Ordinarily, data output flows through a monitor ROM routine *
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* called "COUT" ($FDED). COUT contains a "JMP (CSW)" instruc- *
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* tion. CSW points to the address of the peripheral to which *
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* output should be sent. For instance, if output is destined *
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* for the screen, CSW points to a monitor routine called *
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* "COUT1" ($FDF0). After COUT1 does some homework, it sends *
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* the character to the screen. Similarly, input normally *
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* flows through the "RDKEY" ($FD0C) routine located in monitor *
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* ROM. This routine contains a "JMP (KSW)" instruction. KSW *
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* normaly points to the monitor routine known as "KEYIN" *
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* ($FD1D). KEYIN accepts input from the keyboard. *
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* Now, let's put DOS back into the picture: *
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* - When a coldstart is done, the INITIOHK ($A851) routine in *
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* DOS initializes the I/O hooks to point at DOS's own input *
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* (INPTINCP, $9E8A) and output (OPUTINCP, $9E8D) handlers. *
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* Therefore, when DOS is up, any routine that requests input *
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* or output, must go through DOS'S own I/O handlers to be *
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* screened. The I/O handlers decide whether the input is to *
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* be taken from the keyboard or the disk and whether output *
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* should be sent to the screen, the disk, the printer or any *
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* other output device. For example, let's assume that we are *
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* running a BASIC program that calls for a character to be *
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* printed on the screen. When BASIC's "PRINT" statement is *
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* encountered, execution flows to the "JMP (CSW)" instruction *
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* in the monitor at COUT ($FDED). Because the output hook *
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* (CSW) points to DOS'S output handler, execution flows to *
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* OPUTINCP ($9E8D). OPUTINCP looks at the command line and *
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* discovers that the character is to be sent to the screen. *
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* It then calls PREP4DOS ($9ED1) to repoint the output hook at *
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* the true output handler (COUT1, $FDF0) and JSR's to COUT1. *
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* After COUT1 puts the character on the screen, execution *
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* returns to DOS. DOS does some homework and then execution *
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* flows back to BASIC. Before DOS is exited however, it again *
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* calls the INITIOHK routine to reset the I/O hooks to point *
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* at DOS's own I/O handlers. *
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* In otherwords, DOS acts like an omnipotent peeping Tom. He *
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* screens all input and output and then takes whatever action he *
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* deems appropriate. *
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* *
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* PARLEZ VOUS APPLESOFT? *
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* The first three models of Apple II computers were based *
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* on two different versions of ROM. Old Apples II's contained *
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* Integer basic in ROM whereas the newer Apple II+/IIe's were *
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* built with Applesoft basic in ROM. In order to accommodate *
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* both types of machines and their hapless programmers, Apple *
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* made the DOS Master disk bilingual. When you boot with this *
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* disk, DOS determines what kind of machine you're using and *
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* what language to load on the RAM card. For example, if you *
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* are using a II+ or IIe, the system master disk automatically *
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* runs the "HELLO" program. The "HELLO" program then loads a *
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* file called "INTBASIC" onto the RAM card. (INTBASIC is a *
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* binary file which represents an image of the Integer basic *
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* language.) Similarly, if you're using an old Apple II *
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* machine, the system master will run an Integer program *
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* (confusingly called, "APPLESOFT") which loads a file called *
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* "FPBASIC" onto the language card. (FPBASIC is a binary file *
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* which represents an image of Applesoft Floating Point Basic.) *
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* Because this ram-resident version of Applesoft has gone *
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* through several evolutionary stages, it is referred to in the *
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* literature by several different names: disk-based Applesoft, *
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* Applesoft RAM, cassette Applesoft, RAM Applesoft and A(RAM). *
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* Therefore, because the language card can contain a *
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* different language than the motherboard, the cold- and warm- *
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* start routines must determine not only which language is *
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* presently active, but also if the active language is on the *
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* card or motherboard. *
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* *
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* FLAGS AND EXECUTION PATTERNS. *
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* The status register is used to distinguish between the *
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* cold- and warmstart execution patterns. In some cases (ex. *
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* CMWRMCLD, $9DD1), the carry flag is used to determine if a *
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* cold- or warmstart is being executed. However, in other cases *
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* (ex. OPUTINCP, $9E8D) and INPTINCPT, $9E81), a specific memory *
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* location is used as a flag. Because several flags appear to *
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* have similar connotations but are set and tested at different *
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* times, one must keep close tabs on the different flag *
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* conditions: *
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* (AA51) *
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* CONDNFLG = I/O condition flag. *
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* = $00 = warmstart. *
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* = $01 = reading a file. *
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* = $C0 = using A(RAM). *
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* (AA52) *
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* OPUTCOND = character output condition flag. *
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* = $00 = evaluate start of input line. *
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* = $01 = got a DOS control character, so collect *
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* the DOS command. *
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* = $02 = not a DOS command, so just print a <cr> *
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* and return to the caller. *
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* = $03 = get ready to process an INPUT statement. *
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* = $04 = writing data to the disk. *
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* = $05 = evaluate the first char of the data line *
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* read from the disk. *
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* = $06 = ignore a question mark prompt & reset to *
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* condition 0. *
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* (AAB3) *
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* EXECFLAG = non-zero value (actually first char of the *
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* name of the exec file) = presently EXECing. *
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* = $00 = not execing a file. *
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* (AAB6) *
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* ACTBSFLG = active basic flag. *
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* = $00 = integer. *
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* = $40 = A(ROM). *
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* = $80 = A(RAM). *
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* (AAB7) *
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* RUNTRUPT = run intercept flag. *
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* = $00 = RUN command was NOT interrupted. *
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* = $40 = RUN command was interrupted to load *
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* a file when using A(ROM). *
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* = $80 = RUN command was interrupted to load *
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* a file when using A(RAM). *
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* (E000) *
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* BASICCLD = BASIC's coldstart routine. *
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* (First byte distinguishes type of ROM used.) *
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* = $20 = opcode for "JSR", denotes Integer. *
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* = $40 = opcode for "JMP", denotes A(ROM). *
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* *
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* To help keep things in perspective, the general features *
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* of the cold- and warmstart routines are described below: *
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* *
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* COLDSTART - determine what language & ROM is being used *
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* and fill in the active basic entry point *
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* vector table accordingly. *
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* - reset the I/O hooks so that DOS can intercept *
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* all input & output. *
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* - simulate a "NOMON" command. *
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* - rebuild the DOS buffers (resetting HIMEM, *
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* discarding strings and wiping out the prgm). *
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* - print a prompt and wait for input. *
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* WARMSTART - reset the language card to the language used *
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* when DOS was last cold started. *
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* - reset the I/O hooks so DOS can intercept all *
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* input and output. *
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* - simulate a "NOMON" command. *
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* - (note that the program and variables are left *
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* intact.) *
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* *
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*================================================================*
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* DOS's coldstart routine.
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* (P.S. Don't confuse with basic's coldstart
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* routine (BASICCLD, $E000).)
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(9D84)
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DOSCOLD LDA IBSLOT ;Slot * 16 from RWTS's IOB table.
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LSR ;Divide by 16.
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LSR
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LSR
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LSR
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STA SLOTPRSD ;Put slot in parsed table.
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LDA IBDRVN ;Drive # from RWTS's IOB.
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(9D91) STA DRVPRSD ;Put drive in parsed table.
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* Check which basic is in ROM.
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(9D94) LDA BASICCLD ;Get identifying byte: $20 = integer
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EOR #$20 ; $40 = A(ROM).
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(9D99) BNE ISFPROM ;Branch if FP is in ROM.
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* Integer basic is active.
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(9D9B)
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ISINT STA ACTBSFLG ;Set active basic flag to denote
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;integer ($00).
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* Copy image of INTEGER basic's entry point vector
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* table to the active entry point vector table.
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(9D9E) LDX #10
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INT2BSIC LDA IMGINTV-1,X
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STA CHAINTRY-1,X
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DEX
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BNE INT2BSIC
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(9DA9) JMP BYPASWRM
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------------
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* Copy image of APPLESOFT's entry point vector
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* table to the active entry point vector table.
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(9DAC)
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ISFPROM LDA #$40 ;Set active basic flag to #$40 to
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STA ACTBSFLG ;signal using Applesoft ROM.
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LDX #12
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AROM2BSC LDA IMGFPV-1,X
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STA CHAINTRY-1,X
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DEX
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BNE AROM2BSC
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BYPASWRM SEC ;(c) = 1, signal for coldstart.
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(9DBC) ;(c) = 0, signal for warmstart.
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(9DBD) BCS CMWRMCLD ;Force branch to bypass part of the
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;warmstart routine.
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(9DD1)
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CMWRMCLD PHP ;Save (c) denoting if warm or cold starting.
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JSR INITIOHK ;Initialize the I/O hooks.
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* Initialize the I/O hooks so that DOS intercepts
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* all input & output. For instance, if a routine
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* encounters a "COUT JMP (CSW)", then execution will
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* actually flow to DOS's output routine (OPUTINCP,
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* $9EBD). Similarly, any routine that refers to
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* "RDKEY JMP (KSW)" will actually jump to DOS's
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* input routine (INPTINCP, $9E81).
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*
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* The true (ie. normal) hooks are saved,
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* ex: KSW: KEYIN --> KSWTRUE: KEYIN.
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* CSW: COUT1 --> CSWTRUE: COUT1.
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* The intercepts are then set as follows:
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* ADINPTCP: INPTINCP --> KSW: INPTINCP.
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* ADOPUTCP: OPUTINCP --> CSW: OPUTINCP.
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* Check if input hook needs to be reset.
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(A851)
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INITIOHK LDA KSW+1
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CMP ADINPTCP+1
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(A856) BEQ CKOUTHK ;Input hook already points to DOS's
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;input handler, so go check output hook.
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* Reset input hook to point to DOS.
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(A858) STA KSWTRUE+1 ;KSW: KEYIN --> KSWTRUE: KEYIN
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LDA KSW
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STA KSWTRUE
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LDA ADINPTCP ;ADINPTCP: INPTINCP --> KSW: INPTINCP
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STA KSW
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LDA ADINPTCP+1
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(A868) STA KSW+1
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* Check if output hook needs to be reset.
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(A86A)
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CKOUTHK LDA CSW+1
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CMP ADOPUTCP+1
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(A86F) BEQ SETHKRTN ;Output hook already points to DOS's
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;output handler, so go exit.
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* Reset output hook to point to DOS.
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(A871) STA CSWTRUE+1 ;CSW: COUT1 --> CSWTRUE: COUT1.
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LDA CSW
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STA CSWTRUE
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LDA ADOPUTCP ;ADOPUTCP: OPUTINCP --> CSW: OPUTINCP
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STA CSW
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LDA ADOPUTCP+1
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STA CSW+1
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SETHKRTN RTS
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(A883)
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(9DD5) LDA #0
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(9DD7) STA CIOCUMUL ;Simulate a "NOMON" command. Note that we
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;can "NOP" out this instruction to defeat
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;"NOMONCIO" when cold- or warmstarting.
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(9DDA) STA OPUTCOND ;Set condition 0.
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PLP ;Get status back off the stack.
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ROR ;Use it to set CONDNFLG=$00 for warmstart
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STA CONDNFLG ;or =$80 for coldstart.
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(9DE2) BMI LANGCOLD ;Branch if doing coldstart.
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(9DE7)
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LANGCOLD JMP (TOCLDVEC) ;Jumps to BASIC's coldstart routine
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------------ ;(BASICCLD) at $E000.
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* NOTE: YOU ARE LEAVING THE COMFORTABLE WORLD
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* OF DOS AND ENTERING THE MURKY REALM OF BASIC.
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(E000)
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BASICCLD JMP BSCOLDST ;Go to basic's main coldstart.
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------------
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* Basic's MAIN coldstart routine.
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(F128)
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BSCOLDST LDX #$FF ;Set hi byte of current line # to $FF to
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STX CURLIN+1 ;signal immediate (direct) mode.
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LDX #$FB ;RESET STACK POINTER to point to $1FB so
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(F12E) TXS ;enough space is left on stack for the first
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;set of link pointers & line number associated
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;with an Applesoft program line.
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* Set GOWARM & GOSTROUT jump vectors to point to
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* coldstart, so no matter what happens, we will
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* always come back to do a coldstart. (Later, once
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* the coldstart is completed, the jump vectors will
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* be changed.)
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(F12F) LDA #<BSCOLDST
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LDY #>BSCOLDST
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STA GOWARM+1 ; GOWARM: JMP BSCOLDST
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STA GOWARM+2
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STA GOSTROUT+1 ; GOSTROUT: JMP BSCOLDST
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STY GOSTROUT+2
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(F13B) JSR NORMAL ;Simulate a "NORMAL" statement.
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* Set the normal mode.
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* (INVFLG: #$FF and FLSHMSK: #$00 for normal mode.)
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(F273)
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NORMAL LDA #$FF
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BNE NORMINV ;ALWAYS.
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INVERSE LDA #$3F
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NORMINV LDX #0
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SETINV STA INVFLG
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STX FLSHMSK
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(F27F) RTS
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|
|
|
||
|
|
* Put a "JMP" opcode in GOWARM, GOSTROUT,
|
||
|
|
* JMPADRS & USR jump vectors.
|
||
|
|
(F13E) LDA #$4C ;Opcode for "JMP" instruction.
|
||
|
|
STA GOWARM
|
||
|
|
STA GOSTROUT
|
||
|
|
STA JMPADRS
|
||
|
|
(F146) STA USR
|
||
|
|
|
||
|
|
* Finish setting up the USR jump vector.
|
||
|
|
(F148) LDA #<IQERR ;Point the USR at illegal-quantity-error routine.
|
||
|
|
LDY #>IQERR
|
||
|
|
STA USR+1
|
||
|
|
(F14E) STY USR+2
|
||
|
|
|
||
|
|
* Copy the image of the CHRGET routine and
|
||
|
|
* the random number seed into page zero.
|
||
|
|
* (NOTE: There is a bug in this routine
|
||
|
|
* because it doesn't copy all of the random
|
||
|
|
* number seed. One byte is left behind!)
|
||
|
|
(F150) LDX #$1C ;BUG - should be #$1D.
|
||
|
|
MV2ZPG LDA CHRGETFP-1,X ;Get byte of orignal and copy it to
|
||
|
|
STA CHRGET-1,X ;to its zero page location.
|
||
|
|
STX SPEEDFLG ;On the last pass, set speed to 255 (SPEEDFLG=1).
|
||
|
|
DEX
|
||
|
|
(F15A) BNE MV2ZPG
|
||
|
|
|
||
|
|
* Set up more zero-page locations.
|
||
|
|
(F15C) STX TRCFLG ;Simulate a "NOTRACE" statement.
|
||
|
|
TXA
|
||
|
|
STA TEMPRY ;Contains a #$00 expect during INIT routine.
|
||
|
|
STA LASTPT+1 ;Always equals $00.
|
||
|
|
PHA ;Put a $00 on the stack at $1FB (not used).
|
||
|
|
LDA #3 ;Set the length for the temporary string
|
||
|
|
STA DSCLEN ;descriptor for use by garbage subroutines.
|
||
|
|
(F168) JSR CRDO ;Go print a <cr>.
|
||
|
|
|
||
|
|
(DAFB)
|
||
|
|
CRDO LDA #$0D ;Positive ASCII for <cr>.
|
||
|
|
(DAFD) JSR OUTDO
|
||
|
|
|
||
|
|
(DB5C)
|
||
|
|
OUTDO ORA #$80 ;Convert to neg ASCII.
|
||
|
|
CMP #" " ;Is it a ctrl char?
|
||
|
|
BCC GODOPUT ;Branch if ctrl char.
|
||
|
|
ORA FLSHMSK ;$40 for FLASH, $00 for INVERSE or NORMAL.
|
||
|
|
GODOPUT JSR COUT ;Go to output handling routine.
|
||
|
|
(DB64)
|
||
|
|
|
||
|
|
(FDED)
|
||
|
|
COUT JMP (CSW) ;DOS intercepts output via CSW hook.
|
||
|
|
------------
|
||
|
|
|
||
|
|
* DOS's output intercept routine.
|
||
|
|
(9EBD)
|
||
|
|
OPUTINCP JSR PREP4DOS
|
||
|
|
|
||
|
|
* Prepare for processing by DOS.
|
||
|
|
(9ED1)
|
||
|
|
PREP4DOS STA ASAVED ;Save (a), (y) & (x)
|
||
|
|
STX XSAVED ;registers.
|
||
|
|
STY YSAVED
|
||
|
|
TSX ;Adjust stack ptr &
|
||
|
|
INX ;save it so when we
|
||
|
|
INX ;later restore it &
|
||
|
|
(9EDD) STX STKSAVED ;then hit an "RTS"
|
||
|
|
;we will return to
|
||
|
|
;$DB67.
|
||
|
|
|
||
|
|
* Handy entry point frequently
|
||
|
|
* used by assembly language
|
||
|
|
* programmers to disconnect
|
||
|
|
* DOS completely.
|
||
|
|
(9EE0)
|
||
|
|
UNCONDOS LDX #3
|
||
|
|
SETRUHKS LDA CSWTRUE,X ;Restore the I/O
|
||
|
|
STA CSW,X ;hooks 2 pt 2 the
|
||
|
|
DEX ;true I/O handlers.
|
||
|
|
BPL SETRUHKS ;4 bytes to move
|
||
|
|
(9EEA) RTS ;(0 to 3).
|
||
|
|
|
||
|
|
* Use current OPUTCOND value to index table containing
|
||
|
|
* address of output condition handlers. Do a "stack jump"
|
||
|
|
* to the appropriate condition handler entry point.
|
||
|
|
(9EC0) LDA OPUTCOND
|
||
|
|
ASL ;Times 2 cause 2 bytes/address.
|
||
|
|
TAX ;Set (x) to index tbl of entry pt addrs.
|
||
|
|
LDA OUTHNDTB+1,X ;Put adr of output handler on stack
|
||
|
|
PHA ;(hi byte first) and then do a "stack jump"
|
||
|
|
LDA OUTHNDTB,X ;to the appropriate entry point.
|
||
|
|
PHA
|
||
|
|
LDA ASAVED ;Get char to be printed.
|
||
|
|
(9ED0) RTS ;Execute the "stack jump".
|
||
|
|
|
||
|
|
.
|
||
|
|
.
|
||
|
|
STACK JUMP TO OPUTHDL0
|
||
|
|
.
|
||
|
|
.
|
||
|
|
* Output handler 0.
|
||
|
|
* (Evaluate start of line.)
|
||
|
|
(9EEB)
|
||
|
|
OPUTHDL0 LDX RUNTRUPT ;Was a RUN interrupted?
|
||
|
|
(9EEE) BEQ NONTRUPT ;Branch if not.
|
||
|
|
|
||
|
|
* File not being read.
|
||
|
|
(9EF3)
|
||
|
|
NONTRUPT LDX CONDNFLG ;Are we doing a warmstart ($00),
|
||
|
|
;coldstart ($80), using A(RAM) ($C0)
|
||
|
|
;or doing a READ ($01)?
|
||
|
|
(9EF6) BEQ SETIGNOR ;Branch if warmstarting.
|
||
|
|
|
||
|
|
* Not doing warmstart, so check (a) to see
|
||
|
|
* if using "?" associated with READing an
|
||
|
|
* INPUT statement.
|
||
|
|
(9EF8) CMP #"?"
|
||
|
|
BEQ OPUTHDL6 ;Branch if doing a READ.
|
||
|
|
CMP PROMPT ;Is (a) = the prompt character?
|
||
|
|
BEQ SET2EVAL ;Branch if about to print a prompt.
|
||
|
|
SETIGNOR LDX #2 ;Set condition 2 for default to signal
|
||
|
|
STX OPUTCOND ;that non-DOS commands should be ignored.
|
||
|
|
CMP DCTRLCHR ;Is the char = DOS's control character?
|
||
|
|
(9F08) BNE OPUTHDL2 ;No.
|
||
|
|
|
||
|
|
* Output handler 2.
|
||
|
|
* (Ignore non-DOS commands.)
|
||
|
|
(9F23)
|
||
|
|
OPUTHDL2 CMP #$8D ;Is char a <rtn>?
|
||
|
|
BNE DSPLYALL ;Yes - fall thru.
|
||
|
|
SET2EVAL LDX #0 ;Set condition 0 - evaluate start
|
||
|
|
STX OPUTCOND ;of line.
|
||
|
|
(9F2C) JMP DSPLYALL ;Go display char unconditionally.
|
||
|
|
------------
|
||
|
|
|
||
|
|
* Display the char.
|
||
|
|
(9FA4)
|
||
|
|
DSPLYALL JSR RESTOREG
|
||
|
|
|
||
|
|
* Restore (a), (y) & (x) registers.
|
||
|
|
(9FBA)
|
||
|
|
RESTOREG LDA ASAVED
|
||
|
|
LDY YSAVED
|
||
|
|
LDX XSAVED
|
||
|
|
SEC ;Why?????
|
||
|
|
(9FC4) RTS
|
||
|
|
|
||
|
|
(9FA7) JSR GODSPLY
|
||
|
|
|
||
|
|
* PRINT A <CR> THROUGH THE TRUE
|
||
|
|
* OUTPUT HANDLER.
|
||
|
|
(9FC5)
|
||
|
|
GODSPLY JMP (CSW)
|
||
|
|
------------
|
||
|
|
|
||
|
|
(FDF0)
|
||
|
|
COUT1 .
|
||
|
|
.
|
||
|
|
(See dis'mbly in APPLE II REFERENCE MANUAL.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
* Save registers.
|
||
|
|
(9FAA) STA ASAVED ;Save (a), (y) & (x) registers.
|
||
|
|
STY YSAVED
|
||
|
|
(9FB0) STX XSAVED
|
||
|
|
|
||
|
|
* Reset hooks & stack pointer.
|
||
|
|
(9FB3)
|
||
|
|
DOSEXIT JSR INITIOHK ;Reset DOS hooks.
|
||
|
|
|
||
|
|
* Initialize the I/O hooks so that DOS
|
||
|
|
* intercepts all input & output.
|
||
|
|
(A851)
|
||
|
|
INITIOHK .
|
||
|
|
.
|
||
|
|
(See dis'mbly above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
* Reset stack pointer & retrieve registers.
|
||
|
|
(9FB6) LDX STKSAVED ;Retrieve the saved stack pointer value
|
||
|
|
TXS ;& reset the stack to return to caller.
|
||
|
|
RESTOREG LDA ASAVED ;Restore (a), (y) & (x) registers.
|
||
|
|
LDY YSAVED
|
||
|
|
LDX XSAVED
|
||
|
|
SEC ;Return to routine that called routine
|
||
|
|
(9FC4) RTS ;that contained "JSR PREP4DOS" instruc.
|
||
|
|
|
||
|
|
(DB67) AND #$7F ;Convert char back to positive ASCII.
|
||
|
|
PHA ;Save it on the stack.
|
||
|
|
LDA SPEEDFLG ;Delay in accordance with speed setting.
|
||
|
|
(DB6C) JSR WAIT
|
||
|
|
|
||
|
|
* Monitor ROM's main delay routine.
|
||
|
|
* Delay z number of cycles based on
|
||
|
|
* the formula:
|
||
|
|
* z = ((5 * a^2) + (27 * a) + 26) / 2
|
||
|
|
* where a = value in accumulator in entry.
|
||
|
|
(FCA8)
|
||
|
|
WAIT SEC ;Prepare for subtraction.
|
||
|
|
WAIT2 PHA ;Save (a) on the stack.
|
||
|
|
WAIT3 SBC #1 ;Keep on reducing (a)
|
||
|
|
BNE WAIT3 ;until it equals zero.
|
||
|
|
PLA ;Get original val of (a) off stack.
|
||
|
|
SBC #1 ;Reduce original (a) down to 0 again.
|
||
|
|
BNE WAIT2
|
||
|
|
(FCB3) RTS
|
||
|
|
|
||
|
|
(DB6F) PLA ;Get saved char back from stack.
|
||
|
|
(DB70) RTS
|
||
|
|
|
||
|
|
(DB00) EOR #$FF ;No reason for this?
|
||
|
|
(DB02) RTS
|
||
|
|
|
||
|
|
(F16B) .
|
||
|
|
.
|
||
|
|
- find the highest RAM location in the machine.
|
||
|
|
- put the address (plus 1) of the highest memory
|
||
|
|
location available to Applesoft in MEMSIZ ($73).
|
||
|
|
- set end of free space/top of string storage (FRETOP, $6F).
|
||
|
|
- turn off the $D6 run protection switch.
|
||
|
|
- put a $00 in $800.
|
||
|
|
- make sure that there is at least 1 page of free
|
||
|
|
space between the start of the Applesoft program
|
||
|
|
(TXTTAB, $67) and the end of free space (FRETOP, $6F).
|
||
|
|
- simulate a NEW (& CLEAR) command. (Adjusts almost
|
||
|
|
all major zero page pointers.)
|
||
|
|
- set USR vector jump ($0A - $0C).
|
||
|
|
- set GOWARM vector jump ($00 - $02).
|
||
|
|
.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(F1D2) JMP (GOWARM+1) ;Jump to basic's main command loop
|
||
|
|
------------ ;(ie. warmstart routine) called RESTART.
|
||
|
|
|
||
|
|
* BASIC'S WARMSTART ROUTINE.
|
||
|
|
* Enter with OPUTCOND = 0 and CONDNFLG = $80
|
||
|
|
* for coldstart or $00 for warmstart.
|
||
|
|
(D43C)
|
||
|
|
RESTART JSR CRDO
|
||
|
|
|
||
|
|
* Print a <cr> through basic, DOS's
|
||
|
|
* output handler (OPUTINCP) & the monior.
|
||
|
|
(DAFB)
|
||
|
|
CRDO .
|
||
|
|
.
|
||
|
|
(See dis'mbly above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(DB02) RTS
|
||
|
|
|
||
|
|
* Print the Applesoft prompt through
|
||
|
|
* Basic, DOS's output handler (OPUTINCP)
|
||
|
|
* and the monitor. Then, intercept input
|
||
|
|
* through DOS's input handler (INPTINCP).
|
||
|
|
(D43F) LDX #$DD ;RH brackett for Applesoft prompt.
|
||
|
|
(D441) JSR INLINPL2
|
||
|
|
|
||
|
|
(D52E)
|
||
|
|
INLINPL2 STX PROMPT
|
||
|
|
(D530) JSR GETLN
|
||
|
|
|
||
|
|
* Get a line of input.
|
||
|
|
(FD6A)
|
||
|
|
GETLN LDA PROMPT ;Print prompt.
|
||
|
|
(FD6C) JSR COUT
|
||
|
|
|
||
|
|
(FDED)
|
||
|
|
COUT JMP (CSW) ;Output hook pts to DOS's output handler.
|
||
|
|
------------
|
||
|
|
|
||
|
|
* DOS's output intercept routine.
|
||
|
|
(9EBD)
|
||
|
|
OPUTINCP JSR PREP4DOS
|
||
|
|
|
||
|
|
(9ED1)
|
||
|
|
PREP4DOS STA ASAVED ;Save (a), (y) & (x)
|
||
|
|
STX XSAVED ;registers.
|
||
|
|
STY YSAVED
|
||
|
|
TSX ;Adjust stk ptr and
|
||
|
|
INX ;save it so that
|
||
|
|
INX ;when we later
|
||
|
|
(9EDD) STX STKSAVED ;restore it and hit
|
||
|
|
;an "RTS", we can
|
||
|
|
;return to $FD6F.
|
||
|
|
|
||
|
|
* Restore the I/O hooks to point to the
|
||
|
|
* true I/O handlers, ex:
|
||
|
|
* KSWTRUE: KEYIN --> KSW: KEYIN.
|
||
|
|
* CSWTRUE: COUT1 --> CSW: COUT1.
|
||
|
|
(9EE0)
|
||
|
|
UNCONDOS LDX #3
|
||
|
|
SETRUHKS LDA CSWTRUE,X
|
||
|
|
STA CSW,X
|
||
|
|
DEX
|
||
|
|
BPL SETRUHKS ; 4 bytes to move
|
||
|
|
(9EEA) RTS ;(0 to 3).
|
||
|
|
|
||
|
|
* Use current OPUTCOND value to index table containing
|
||
|
|
* address of output condition handlers. Do a "stack jump"
|
||
|
|
* to the appropriate condition handler entry point.
|
||
|
|
(9EC0) LDA OPUTCOND
|
||
|
|
ASL ;Times 2 cause 2 bytes/address.
|
||
|
|
TAX ;Set (x) to index table of addresses.
|
||
|
|
LDA OUTHNDTB+1,X ;Put adr of output handler on stack
|
||
|
|
PHA ;(hi byte first) and then do a "stack jump"
|
||
|
|
LDA OUTHNDTB,X ;to the appropriate entry point.
|
||
|
|
PHA
|
||
|
|
LDA ASAVED ;Get char to be printed.
|
||
|
|
(9ED0) RTS ;Execute the "stack jump".
|
||
|
|
|
||
|
|
.
|
||
|
|
.
|
||
|
|
STACK JUMP TO OPUTHDL0
|
||
|
|
.
|
||
|
|
.
|
||
|
|
* Output handler 0.
|
||
|
|
* (Evaluate start of line.)
|
||
|
|
(9EEB)
|
||
|
|
OPUTHDL0 LDX RUNTRUPT ;Was a RUN interrupted?
|
||
|
|
(9EEE) BEQ NONTRUPT ;Branch if not.
|
||
|
|
|
||
|
|
(9EF3)
|
||
|
|
NONTRUPT LDX CONDNFLG ;Are we doing a warmstart ($00),
|
||
|
|
;coldstart ($80), using A(RAM) ($C0)
|
||
|
|
;or doing a read ($01)?
|
||
|
|
(9EF6) BEQ SETIGNOR ;Branch if warmstarting.
|
||
|
|
|
||
|
|
* Not doing warmstart, so check (a) to see
|
||
|
|
* if using "?" associated with READing an
|
||
|
|
* INPUT statement.
|
||
|
|
(9EF8) CMP #"?"
|
||
|
|
(9EFA) BEQ OPUTHDL6 ;Branch if getting ready
|
||
|
|
;to read a text file byte.
|
||
|
|
(9EFC) CMP PROMPT ;Are we printing a prompt?
|
||
|
|
(9EFE) BEQ SET2EVAL ;Branch if about to print prompt.
|
||
|
|
|
||
|
|
(9F27)
|
||
|
|
SET2EVAL LDX #0 ;SET CONDITION0 - evaluate start of line.
|
||
|
|
STX OPUTCOND
|
||
|
|
(9F2C) JMP DSPLYALL ;Go display char.
|
||
|
|
------------
|
||
|
|
|
||
|
|
* Display the char.
|
||
|
|
(9FA4)
|
||
|
|
DSPLYALL JSR RESTOREG
|
||
|
|
|
||
|
|
* Restore (a), (y) & (x) registers.
|
||
|
|
(9FBA)
|
||
|
|
RESTOREG LDA ASAVED
|
||
|
|
LDY YSAVED
|
||
|
|
LDX XSAVED
|
||
|
|
SEC ;Why?????
|
||
|
|
(9FC4) RTS
|
||
|
|
|
||
|
|
(9FA7) JSR GODSPLY
|
||
|
|
|
||
|
|
(9FC5)
|
||
|
|
GODSPLY JMP (CSW)
|
||
|
|
------------
|
||
|
|
|
||
|
|
* PRINT APPLESOFT PROMPT through
|
||
|
|
* the true output handler.
|
||
|
|
(FDF0)
|
||
|
|
COUT1 .
|
||
|
|
.
|
||
|
|
- print char thru true output handler.
|
||
|
|
(See dis'mbly in APPLE II REFERENCE MANUAL.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
* Save registers & reset hooks.
|
||
|
|
(9FAA) STA ASAVED ;Save (a), (y) & (x) registers.
|
||
|
|
STY YSAVED
|
||
|
|
(9FB0) STX XSAVED
|
||
|
|
|
||
|
|
* Routine to exit DOS.
|
||
|
|
(9FB3)
|
||
|
|
DOSEXIT JSR INITIOHK
|
||
|
|
|
||
|
|
* Initialize the I/O hooks so that DOS
|
||
|
|
* intercepts all input & output.
|
||
|
|
(A851)
|
||
|
|
INITIOHK .
|
||
|
|
.
|
||
|
|
(See dis'mbly given above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
(9FB6) LDX STKSAVED ;Retrieve the saved stack pointer val
|
||
|
|
TXS ;& reset the stack to return to caller.
|
||
|
|
RESTOREG LDA ASAVED ;Restore (a), (y) & (x) registers.
|
||
|
|
LDY YSAVED
|
||
|
|
LDX XSAVED
|
||
|
|
SEC ;Return to the routine that called the
|
||
|
|
(9FC4) RTS ;routine that contained the "JSR PREP4DOS"
|
||
|
|
;instruction.
|
||
|
|
|
||
|
|
* GET A SINGLE BYTE OF INPUT.
|
||
|
|
(FD6F) LDX #1
|
||
|
|
BCKSPC TXA ;Force fall thru to next instruction.
|
||
|
|
BEQ GETLNZ
|
||
|
|
DEX ;Initialize (x) = 0 as index to input buf.
|
||
|
|
NXTCHAR JSR RDCHAR
|
||
|
|
(FD75)
|
||
|
|
|
||
|
|
* Routine to read an input byte.
|
||
|
|
(FD35)
|
||
|
|
RDCHAR JSR RDKEY
|
||
|
|
|
||
|
|
(FD0C)
|
||
|
|
RDKEY LDY CH ;Get horiz cursor
|
||
|
|
;pos'n 4 nxt char.
|
||
|
|
(FD0E) LDA (BASL),Y ;Pick up char in next
|
||
|
|
(FD10) PHA ;screen pos'n & save
|
||
|
|
;it on the stack.
|
||
|
|
(FD11) AND #$3F ;Convert char to
|
||
|
|
ORA #$40 ;flashing.
|
||
|
|
(FD15) STA (BASL),Y ;Put flashing char
|
||
|
|
;on scrn to serve
|
||
|
|
;as cursor.
|
||
|
|
(FD17) PLA ;Get char back that
|
||
|
|
;cursor is replacing.
|
||
|
|
;(Need it in case do
|
||
|
|
;bkspc or -> and
|
||
|
|
;want to reinstate
|
||
|
|
;orig char on scrn.
|
||
|
|
(FD18) JMP (KSW) ;Input hook still
|
||
|
|
------------ ;pointing to DOS.
|
||
|
|
|
||
|
|
(9E81)
|
||
|
|
INPTINCP JSR PREP4DOS ;Save regs & stk ptr
|
||
|
|
|
||
|
|
* Adjust & save stk
|
||
|
|
* ptr so can later
|
||
|
|
* rtn to $FD38.
|
||
|
|
* Pt hks at true
|
||
|
|
* I/O handlers.
|
||
|
|
(9ED1)
|
||
|
|
PREP4DOS .
|
||
|
|
.
|
||
|
|
(See dis'mbly
|
||
|
|
above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
(9E84) LDA CONDNFLG ;Test if doing
|
||
|
|
(9E87) BEQ INPUTWRM ;warmstart.
|
||
|
|
;Fall thru if
|
||
|
|
;reading.
|
||
|
|
(9E89) PHA ;Save condition flag.
|
||
|
|
LDA ASAVED ;Put substitute
|
||
|
|
STA (BASL),Y ;cursor back on scrn
|
||
|
|
PLA ;Get condition val.
|
||
|
|
(9E90) BMI INPUTCLD ;Branch 4 coldstart.
|
||
|
|
|
||
|
|
|
||
|
|
* Doing a coldstart.
|
||
|
|
(9E95)
|
||
|
|
INPUTCLD JSR KEYCOLD
|
||
|
|
|
||
|
|
* Initial processing
|
||
|
|
* when 1rst keyboard
|
||
|
|
* input request is
|
||
|
|
* made by basic after
|
||
|
|
* a coldstart entry.
|
||
|
|
(9DEA)
|
||
|
|
KEYCOLD .
|
||
|
|
.
|
||
|
|
.............................................
|
||
|
|
. * Test if using A(RAM) or not.
|
||
|
|
. * On entry, (a) = contents of CONDNFLG.
|
||
|
|
. * = $00 = warmstart.
|
||
|
|
. * = $01 = reading.
|
||
|
|
. * = $80 = coldstart.
|
||
|
|
. * = $C0 = using A(RAM).
|
||
|
|
. (9DEA)
|
||
|
|
. KEYCOLD ASL ;(a) * 2 to drop out hi bit.
|
||
|
|
. (9DEB) BPL SKPDARAM ;Branch if not using A(RAM).
|
||
|
|
.
|
||
|
|
. * Using A(RAM) which was loaded via
|
||
|
|
. * Integer basic (ROM).
|
||
|
|
. (9DED) STA ACTBSFLG ;Using A(RAM), set active
|
||
|
|
. ;basic flag to #$80.
|
||
|
|
.
|
||
|
|
. * Copy image of A(RAM)'s entry pt vector
|
||
|
|
. * tbl to the active entry pt vector tbl.
|
||
|
|
. (9DF0) LDX #12
|
||
|
|
. ARAM2BSC LDA IMGARAMV-1,X
|
||
|
|
. STA CHAINTRY-1,X
|
||
|
|
. DEX
|
||
|
|
. (9DF9) BNE ARAM2BSC
|
||
|
|
.
|
||
|
|
. * Blank out the primary file name buffer
|
||
|
|
. * to make sure a "HELLO" file won't be run.
|
||
|
|
. (9DFB) LDX #29 ;30 bytes to copy (0 - 29)
|
||
|
|
. BLNKPRIM LDA SCNDFNBF,X ;Copy blank secondary
|
||
|
|
. STA PRIMFNBF,X ;to primary.
|
||
|
|
. DEX
|
||
|
|
. (9E04) BPL BLNKPRIM
|
||
|
|
.
|
||
|
|
. * Build DOS buffers and set condition.
|
||
|
|
. (9E06)
|
||
|
|
. SKPDARAM LDA MAXDFLT ;Set MXFILVAL to a default
|
||
|
|
. ;value of 3.
|
||
|
|
. (9E09) STA MXFILVAL ;Note: Default value can be
|
||
|
|
. ;changed by setting MAXFDFLT
|
||
|
|
. ;between 1 and 16 & then
|
||
|
|
. ;INITing a disk.
|
||
|
|
. (9E0C) JSR BILDBUFS ;Go build the DOS buffers.
|
||
|
|
.
|
||
|
|
. (A7D4)
|
||
|
|
. BILDBUFS .
|
||
|
|
. .
|
||
|
|
. (Long routine, see dis'mbly
|
||
|
|
. given in the MAXFILES cmd.)
|
||
|
|
. .
|
||
|
|
. .
|
||
|
|
. (RTS)
|
||
|
|
.
|
||
|
|
. (9E0F) LDA EXECFLAG ;Chk if exec file actv.
|
||
|
|
. (9E12) BEQ SKPDEXEC ;Branch if not EXECing.
|
||
|
|
.
|
||
|
|
. (9E1D)
|
||
|
|
. SKPDEXEC JSR RESTAT0
|
||
|
|
.
|
||
|
|
. * Reset CONDNFLG & OPUTCOND
|
||
|
|
. * = 0 to signal file not
|
||
|
|
. * being read & set
|
||
|
|
. * condition to evaluate
|
||
|
|
. * start of line when we
|
||
|
|
. * return to OPUTINCP.
|
||
|
|
. (A75B)
|
||
|
|
. RESTAT0 LDY #0
|
||
|
|
. STY CONDNFLG
|
||
|
|
. STY OPUTCOND
|
||
|
|
. (A763) RTS
|
||
|
|
.
|
||
|
|
. * Check if the disk was just booted.
|
||
|
|
. * (If just booted disk, NDX2CMD contains a $00
|
||
|
|
. * which was etched on the disk when the disk
|
||
|
|
. * was originally booted.)
|
||
|
|
. (9E20) LDA NDX2CMD ;Was last command an "INIT"?
|
||
|
|
. (9E23) BNE OLDBOOT ;No.
|
||
|
|
.
|
||
|
|
. * Disk was just booted, so copy
|
||
|
|
. * the IMAGE of DOS's entry point
|
||
|
|
. * vector table to page 3.
|
||
|
|
. (9E25) LDX #47
|
||
|
|
. STOR3DOS LDA IMGDOSVT,X
|
||
|
|
. STA PG3DOSVT,X
|
||
|
|
. DEX
|
||
|
|
. (9E2E) BPL STOR3DOS
|
||
|
|
.
|
||
|
|
. * Program the reset key to point at
|
||
|
|
. * DOS's warmstart routine.
|
||
|
|
. *
|
||
|
|
. * Note that the reset key can be
|
||
|
|
. * programmed to point at any location
|
||
|
|
. * simply by putting the address of the
|
||
|
|
. * target routine (in low/hi format) in
|
||
|
|
. * #3F2/$3F3. Next, EOR the contents of
|
||
|
|
. * $3F3 with the number #$A5 and put the
|
||
|
|
. * result in $3F4. (If $3F3 EOR #$A5
|
||
|
|
. * is not equal to $3F4, then the disk
|
||
|
|
. * reboots and a coldstart is done.)
|
||
|
|
. (9E30) LDA IMGDOSVT+2
|
||
|
|
. STA RESETVEC+1
|
||
|
|
. EOR #$A5
|
||
|
|
. STA VLDBYTE
|
||
|
|
. LDA IMGDOSVT+1
|
||
|
|
. (9E3E) STA RESETVEC
|
||
|
|
.
|
||
|
|
. * Set the command index to RUN
|
||
|
|
. * the "HELLO" file.
|
||
|
|
. (9E41) LDA #6 ;Command index for RUN.
|
||
|
|
. ;(Can be changed to BRUN,
|
||
|
|
. ;etc.)
|
||
|
|
. (9E43) BNE DOPENDNG ;ALWAYS.
|
||
|
|
.
|
||
|
|
. * Go do the pending command. If the
|
||
|
|
. * disk was just booted, then RUN the
|
||
|
|
. * "HELLO" file. Note: The actual name
|
||
|
|
. * of the HELLO file resides in the primary
|
||
|
|
. * filename buffer. It was written to the
|
||
|
|
. * disk as part of the DOS image when the
|
||
|
|
. * disk was INITed. Therefore, if you want
|
||
|
|
. * to change the name of the HELLO file,
|
||
|
|
. * you must:
|
||
|
|
. * 1) change the file name in the
|
||
|
|
. * file name field section of
|
||
|
|
. * the appropriate directory
|
||
|
|
. * sector. (Easiest to use
|
||
|
|
. * the RENAME command.)
|
||
|
|
. * 2) zap the primary file name
|
||
|
|
. * buf on the disk (trk$01,
|
||
|
|
. * sec $09$, offsets $75 to $92.
|
||
|
|
. (9E4A)
|
||
|
|
. DOPENDNG STA NDX2CMD ;Set cmd index & go do cmd.
|
||
|
|
. (9E4D) JMP DODOSCMD
|
||
|
|
. ------------
|
||
|
|
.
|
||
|
|
. * Do the DOS command.
|
||
|
|
. (A180)
|
||
|
|
. DODOSCMD JSR RESTAT0 ;Reset condition 0.
|
||
|
|
.
|
||
|
|
. * Reset CONDNFLG & OPUTCOND
|
||
|
|
. * to 0 so signal file not
|
||
|
|
. * being read & set
|
||
|
|
. * condition to evaluate
|
||
|
|
. * start of line when we
|
||
|
|
. * return to OPUTINCP.
|
||
|
|
. (A75B)
|
||
|
|
. RESTAT0 LDY #0
|
||
|
|
. STY CONDNFLG
|
||
|
|
. STY OPUTCOND
|
||
|
|
. (A763) RTS
|
||
|
|
.
|
||
|
|
. (A183) JSR CLRFMPRM
|
||
|
|
.
|
||
|
|
. * Zero out the fm parm list.
|
||
|
|
. (A1AE)
|
||
|
|
. CLRFMPRM LDA #0
|
||
|
|
. LDY #$16
|
||
|
|
. ZFMPARM STA FMPRMLST-1,Y
|
||
|
|
. DEY
|
||
|
|
. BNE ZFMPARM
|
||
|
|
. (A1B8) RTS
|
||
|
|
.
|
||
|
|
. * Use the command index to get the
|
||
|
|
. * address (minus 1) of the command's
|
||
|
|
. * entry point. Stick the entry point
|
||
|
|
. * address on the stack (hi byte first)
|
||
|
|
. * & then do a funny jump to execute
|
||
|
|
. * the command.
|
||
|
|
. (A186) LDA NDX2CMD ;(a) = index to command.
|
||
|
|
. (A189) TAX ;(x) = index to table of
|
||
|
|
. ;entry points.
|
||
|
|
. (A18A) LDA CMDTBL+1,X ;Get addr of the cmd's
|
||
|
|
. (A18D) PHA ;routine & put it on the
|
||
|
|
. ;stack (hi byte first).
|
||
|
|
. (A18E) LDA CMDTBL,X
|
||
|
|
. PHA
|
||
|
|
. (A192) RTS ;Do a stack jump to process
|
||
|
|
. ;the command.
|
||
|
|
.
|
||
|
|
. .
|
||
|
|
. .
|
||
|
|
. (EXECUTE THE COMMAND, IE. RUN THE
|
||
|
|
. HELLO FILE WHEN COLDSTARTING.
|
||
|
|
. .
|
||
|
|
. .
|
||
|
|
. NOTE: PARTS OF THE FOLLOWING DIS'MBLY ARE
|
||
|
|
. VERY FRAGMENTED. IT IS ONLY MEANT
|
||
|
|
. TO ILLUSTRATE THE PATTERN OF PROGRAM
|
||
|
|
. FLOW. SEE DIS'MBLY OF RUN & LOAD
|
||
|
|
. COMMANDS FOR MORE DETAIL.
|
||
|
|
.
|
||
|
|
. * Run command handler.
|
||
|
|
. (A4D1)
|
||
|
|
. CMDRUN LDA ACTBSFLG ;Check which basic is
|
||
|
|
. ;current.
|
||
|
|
. ;Contains $40 if A(ROM),
|
||
|
|
. ;$80 if A(RAM), $00 if Int.
|
||
|
|
. (A4D4) BEQ LOAD4RUN ;Branch if using Integer.
|
||
|
|
. (A4D6) STA RUNTRUPT ;SET THE RUN INTERCEPT FLAG
|
||
|
|
. ;TO DENOTE THAT A RUN CMD IS
|
||
|
|
. ;BEING INTERRUPTED TO
|
||
|
|
. ;ACCOMODATE A LOAD.
|
||
|
|
. LOAD4RUN JSR CMDLOAD
|
||
|
|
.
|
||
|
|
. (A413)
|
||
|
|
. CMDLOAD .
|
||
|
|
. .
|
||
|
|
. (Load the HELLO file.)
|
||
|
|
. .
|
||
|
|
. .
|
||
|
|
. - point I/O hooks at DOS.
|
||
|
|
. .
|
||
|
|
. .
|
||
|
|
. (A44D) JMP (RLOCNTRY)
|
||
|
|
. ------------
|
||
|
|
.
|
||
|
|
. (D4F2)
|
||
|
|
. SETLINKS .
|
||
|
|
. .
|
||
|
|
. - Set up ZERO PAGE POINTERS.
|
||
|
|
. - Adjust link pointers in
|
||
|
|
. the HELLO program (so it
|
||
|
|
. is relocatable).
|
||
|
|
.............................................
|
||
|
|
.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
............<<< S T A C K P O I N T E R W A S R E S E T >>>.................................................
|
||
|
|
.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(D43C)
|
||
|
|
RESTART JSR CRDO
|
||
|
|
|
||
|
|
(DAFB)
|
||
|
|
CRDO LDA #$0D ;Positive ASCII for <cr>.
|
||
|
|
(DAFD) JSR OUTDO
|
||
|
|
|
||
|
|
(DB5C)
|
||
|
|
OUTDO ORA #$80 ;Convert to neg ASCII.
|
||
|
|
CMP #" " ;Is it a ctrl char.
|
||
|
|
BCC GODOPUT ;Branch if ctrl char.
|
||
|
|
ORA FLSHMSK ;$40 for FLASH, $00 for INVERSE or NORMAL.
|
||
|
|
GODOPUT JSR COUT ;Go to output handling routine.
|
||
|
|
(DB64)
|
||
|
|
|
||
|
|
(FDED)
|
||
|
|
COUT JMP (CSW)
|
||
|
|
------------
|
||
|
|
|
||
|
|
* DOS's output intercept routine.
|
||
|
|
(9EBD)
|
||
|
|
OPUTINCP JSR PREP4DOS
|
||
|
|
|
||
|
|
* Prepare for processing by DOS.
|
||
|
|
(9ED1)
|
||
|
|
PREP4DOS STA ASAVED ;Save (a), (y) & (x)
|
||
|
|
STX XSAVED ;registers.
|
||
|
|
STY YSAVED
|
||
|
|
TSX ;Adjust stack ptr &
|
||
|
|
INX ;save it wo when we
|
||
|
|
INX ;later restore it &
|
||
|
|
(9EDD) STX STKSAVED ;then hit an "RTS"
|
||
|
|
;we will return to
|
||
|
|
;$DB67.
|
||
|
|
|
||
|
|
* Handy entry point frequently
|
||
|
|
* used by assembly language
|
||
|
|
* programmers to disconnect
|
||
|
|
* DOS completely.
|
||
|
|
(9EE0)
|
||
|
|
UNCONDOS LDX #3
|
||
|
|
SETRUHKS LDA CSWTRUE,X ;Restore the I/O
|
||
|
|
STA CSW,X ;hooks 2 pt 2 the
|
||
|
|
DEX ;true I/O handlers.
|
||
|
|
BPL SETRUHKS ;4 bytes to move
|
||
|
|
(9EEA) RTS ;(0 to 3).
|
||
|
|
|
||
|
|
* Use current OPUTCOND value to index table containing
|
||
|
|
* address of output condition handlers. Do a "stack jump"
|
||
|
|
* to the appropriate condition handler entry point.
|
||
|
|
(9EC0) LDA OPUTCOND
|
||
|
|
ASL ;Times 2 cause 2 bytes/address.
|
||
|
|
TAX ;Set (x) to index tbl of entry pt addrs.
|
||
|
|
LDA OUTHNDTB+1,X ;Put adr of output handler on stack
|
||
|
|
PHA ;(hi byte first) and then do a "stack jump"
|
||
|
|
LDA OUTHNDTB,X ;to the appropriate entry point.
|
||
|
|
PHA
|
||
|
|
LDA ASAVED ;Get char to be printed.
|
||
|
|
(9ED0) RTS ;Execute the "stack jump".
|
||
|
|
|
||
|
|
.
|
||
|
|
.
|
||
|
|
STACK JUMP TO OPUTHDL0
|
||
|
|
.
|
||
|
|
.
|
||
|
|
* Output handler 0.
|
||
|
|
* (Evaluate start of line.)
|
||
|
|
(9EEB)
|
||
|
|
OPUTHDL0 LDX RUNTRUPT ;Was a RUN interrupted?
|
||
|
|
BEQ NONTRUPT ;Branch if not.
|
||
|
|
(9EF0) JMP FINSHRUN ;Finish off the RUN command.
|
||
|
|
------------
|
||
|
|
|
||
|
|
* Finish off the RUN command because
|
||
|
|
* it was interrupted to do a LOAD.
|
||
|
|
(9F78)
|
||
|
|
FINSHRUN LDA #0 ;Zero out the run intercept flag.
|
||
|
|
STA RUNTRUPT
|
||
|
|
(9F7D) JSR INITIOHK ;Reset I/O hooks to pt at DOS.
|
||
|
|
|
||
|
|
* Initialize the I/O hooks so that DOS
|
||
|
|
* intercepts all input & output.
|
||
|
|
(A851)
|
||
|
|
INITIOHK .
|
||
|
|
.
|
||
|
|
(See dis'mbly given above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
(9F80) JMP RUNFPINT ;Jump back into the RUN command
|
||
|
|
------------ ;to finish it off.
|
||
|
|
;NOTE: The stack was reset so
|
||
|
|
;we return to the correct level.
|
||
|
|
|
||
|
|
(A4DC)
|
||
|
|
RUNFPINT JSR CRVIADOS
|
||
|
|
|
||
|
|
(9FC8)
|
||
|
|
CRVIADOS LDA #$8D ;<cr>.
|
||
|
|
(9FCA) JMP GODSPLY ;Go print the <cr>.
|
||
|
|
------------
|
||
|
|
|
||
|
|
(9FC5)
|
||
|
|
GODSPLY JMP (CSW) ;AT THIS POINT IN
|
||
|
|
------------ ;TIME, DOS INTERCEPTS
|
||
|
|
;THE OUTPUT.
|
||
|
|
|
||
|
|
* DOS's output intercept routine.
|
||
|
|
(9EBD)
|
||
|
|
OPUTINCP JSR PREP4DOS
|
||
|
|
|
||
|
|
* Save registers.
|
||
|
|
* Restore the true
|
||
|
|
* I/O hooks.
|
||
|
|
* Adjust & save the
|
||
|
|
* stk ptr so can
|
||
|
|
* later rtn to $A4DF
|
||
|
|
(9ED1)
|
||
|
|
PREP4DOS STA ASAVED
|
||
|
|
STX XSAVED
|
||
|
|
STY YSAVED
|
||
|
|
TSX
|
||
|
|
INX
|
||
|
|
INX
|
||
|
|
STX STKSAVED
|
||
|
|
UNCONDOS LDX #3
|
||
|
|
SETRUHKS LDA CSWTRUE,X
|
||
|
|
STA CSW,X
|
||
|
|
DEX
|
||
|
|
BPL SETRUHKS
|
||
|
|
(9EEA) RTS
|
||
|
|
|
||
|
|
* Use current OPUTCOND value to
|
||
|
|
* index table containing the
|
||
|
|
* address of output condition
|
||
|
|
* handlers. Do a "stack jump"
|
||
|
|
* to the appropriate condition
|
||
|
|
* handler entry point.
|
||
|
|
(9EC0) LDA OPUTCOND
|
||
|
|
(9EC3) ASL ;Times 2 cause 2
|
||
|
|
;bytes/address.
|
||
|
|
(9EC4) TAX ;Set (x) to index
|
||
|
|
;tbl of entry pt
|
||
|
|
;addrs.
|
||
|
|
(9EC5) LDA OUTHNDTB+1,X ;Put adr of
|
||
|
|
PHA ;output handler on
|
||
|
|
LDA OUTHNDTB,X ;stk (hi byte 1rst)
|
||
|
|
(9ECC) PHA ;& do a "stack jump"
|
||
|
|
;to the appropriate
|
||
|
|
;entry point.
|
||
|
|
(9ECD) LDA ASAVED ;Get char to be
|
||
|
|
;printed.
|
||
|
|
(9ED0) RTS ;Execute the "stack
|
||
|
|
;jump".
|
||
|
|
|
||
|
|
.
|
||
|
|
.
|
||
|
|
STACK JUMP TO OPUTHDL0
|
||
|
|
.
|
||
|
|
.
|
||
|
|
* Output handler 0.
|
||
|
|
* (Evaluate start of line.)
|
||
|
|
(9EEB)
|
||
|
|
OPUTHDL0 LDX RUNTRUPT ;Was a RUN
|
||
|
|
;interrupted?
|
||
|
|
(9EEE) BEQ NONTRUPT ;Branch if not.
|
||
|
|
|
||
|
|
* RUN not interrupted.
|
||
|
|
(9EF3)
|
||
|
|
NONTRUPT LDX CONDNFLG ;Get condition.
|
||
|
|
(9EF6) BEQ SETIGNOR ;Branch for warm.
|
||
|
|
|
||
|
|
(9F00)
|
||
|
|
SETIGNOR LDX #2 ;SET CONDITION 2.
|
||
|
|
(9F02) STX OPUTCOND ;Signal ignore
|
||
|
|
;non-DOS cmds.
|
||
|
|
(9F05) CMP DCTRLCHR ;DOS's ctrl char?
|
||
|
|
(9F08) BNE OPUTHDL2 ;No.
|
||
|
|
|
||
|
|
* Output handler 2.
|
||
|
|
* (Ignore non-DOS cmds.)
|
||
|
|
(9F23)
|
||
|
|
OPUTHDL2 CMP #$8D ;<cr>?
|
||
|
|
BNE DSPLYALL ;No.
|
||
|
|
SET2EVAL LDX #0 ;SET CONDITION 0
|
||
|
|
STX OPUTCOND ;(evaluate start
|
||
|
|
(9F2C) JMP DSPLYALL ;of line).
|
||
|
|
------------
|
||
|
|
|
||
|
|
* Display the char.
|
||
|
|
(9FA4)
|
||
|
|
DSPLYALL JSR RESTOREG
|
||
|
|
|
||
|
|
* Restore registers.
|
||
|
|
(9FBA)
|
||
|
|
RESTOREG LDA ASAVED
|
||
|
|
LDY YSAVED
|
||
|
|
LDX XSAVED
|
||
|
|
SEC
|
||
|
|
(9FC4) RTS
|
||
|
|
|
||
|
|
(9FA7) JSR GODSPLY
|
||
|
|
|
||
|
|
(9FC5)
|
||
|
|
GODSPLY JMP (CSW)
|
||
|
|
-------
|
||
|
|
|
||
|
|
* PRINT A <CR> THRU
|
||
|
|
* TRUE OUTPUT HANDLER.
|
||
|
|
(FDF0)
|
||
|
|
COUT1 .
|
||
|
|
.
|
||
|
|
(See dis'mbly in APPLE
|
||
|
|
II REFERENCE MANUAL.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
* Save registers & reset hooks.
|
||
|
|
(9FAA) STA ASAVED
|
||
|
|
STY YSAVED
|
||
|
|
(9FB0) STX XSAVED
|
||
|
|
|
||
|
|
* Routine to exit DOS.
|
||
|
|
(9FB3)
|
||
|
|
DOSEXIT JSR INITIOHK
|
||
|
|
|
||
|
|
* Initialize I/O hks
|
||
|
|
* so DOS intercepts
|
||
|
|
* all input & output.
|
||
|
|
(A851)
|
||
|
|
INITIOHK .
|
||
|
|
.
|
||
|
|
(See dis'mbly above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
(9FB6) LDX STKSAVED ;Restore stk pointer.
|
||
|
|
TXS
|
||
|
|
RESTOREG LDA ASAVED ;Restore registers.
|
||
|
|
LDY YSAVED
|
||
|
|
LDX XSAVED
|
||
|
|
SEC ;Why?????
|
||
|
|
(9FC4) RTS ;RETURN TO THE ROUTINE
|
||
|
|
;THAT CALLED THE
|
||
|
|
;ROUTINE THAT
|
||
|
|
;CONTAINED THE
|
||
|
|
;"JSR PREP4DOS"
|
||
|
|
;INSTRUCTION.
|
||
|
|
|
||
|
|
(A4DF) JSR INITIOHK
|
||
|
|
|
||
|
|
* Initialize I/O hks
|
||
|
|
* so DOS intercepts
|
||
|
|
* all input & output.
|
||
|
|
(A851)
|
||
|
|
INITIOHK .
|
||
|
|
.
|
||
|
|
(See dis'mbly above.)
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(RTS)
|
||
|
|
|
||
|
|
(A4E2) JMP (RUNTRY) ;Go execute the prgm.
|
||
|
|
------------ ;(RUNTRY points to RUNFPROM if using
|
||
|
|
;A(ROM) or FPRAMRUN if using A(RAM)).
|
||
|
|
|
||
|
|
(A4FC)
|
||
|
|
RUNFPROM JSR SETZPTRS
|
||
|
|
|
||
|
|
(D665)
|
||
|
|
SETZPTRS .
|
||
|
|
.
|
||
|
|
- simulate CLEAR & RESTORE statements
|
||
|
|
- reset important zero page pointers
|
||
|
|
- REINTIALIZE THE STACK POINTER TO
|
||
|
|
POINT TO $1F8 (while retaining return
|
||
|
|
address).
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(D696) RTS
|
||
|
|
.
|
||
|
|
.
|
||
|
|
............. <<< S T A C K P O I N T E R W A S R E S E T >>>.........................
|
||
|
|
.
|
||
|
|
.
|
||
|
|
(A4FF) STA PROMPT ;Zero out the prompt & on-err flag.
|
||
|
|
STA ERRFLG
|
||
|
|
(A503) JMP NEWSTT ;Jump into BASIC to execute the program.
|
||
|
|
------------
|
||
|
|
|
||
|
|
(D7D2)
|
||
|
|
NEWSTT .
|
||
|
|
.
|
||
|
|
- EXECUTES THE APPLESOFT PROGRAM.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
- pops in & out of DOS whenever
|
||
|
|
a line containing a PRINT,
|
||
|
|
INPUT or GET is encountered.
|
||
|
|
.
|
||
|
|
.
|
||
|
|
BEQ RESTART
|
||
|
|
|
||
|
|
Once again the RESTART ($D43C) routine
|
||
|
|
is entered. However this time execution
|
||
|
|
flows through DOS's output (OPUTINCP, $9EBD)
|
||
|
|
and input (INPTINCP, $9E81) handlers in a manner
|
||
|
|
different than that depicted above. Because
|
||
|
|
the flags are set as shown below, the computer
|
||
|
|
eventually ends up requesting the operator to
|
||
|
|
input commands via the KEYBOARD:
|
||
|
|
CONDNFLG: $00, ACTBSFLG: $40,
|
||
|
|
RUNTRUPT: $00, and OPUTCOND: $00.
|
||
|
|
The exact execution pattern is shown in the
|
||
|
|
disassembly of the RESTART routine described
|
||
|
|
in the file titled "DOSWARMSTART".
|