424 lines
11 KiB
Plaintext
424 lines
11 KiB
Plaintext
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_REMOTE CONNECTIVITY FOR PORTABLE TERMINALS: PART I_
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by Dan Troy
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[LISTING ONE]
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void process_VT100_input(char *z)
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{
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char data;
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TERMINALP t = (TERMINALP)z; /* default VT100 parameters */
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if(!eof()) /* if character exists in */
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{ /* serial buffer */
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read(&data); /* then read it */
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active = TRUE; /* set global activity flag */
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write_screen(t, data); /* process VT100 character */
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}
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}
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[LISTING TWO]
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typedef struct
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{
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char addlf; /* line feed/new line */
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char keymode; /* cursor/application */
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char insert; /* replace/insert */
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char autowrap; /* off/on */
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char keypad; /* numeric/alternate */
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char origin; /* absolute/relative */
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char kblock; /* keyboard unlock/lock */
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}TERMINAL, *TERMINALP;
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[LISTING THREE]
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init_emulation_mode:
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clr ea ;shut off interrupts
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mov dptr,#emul_processor_address ;get c function address
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mov a,r3 ;get low byte of function
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;from C call
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movx @dptr,a ;save at storage address
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inc dptr ;inc processor address ptr
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mov a,r2 ;get high byte of function
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movx @dptr,a ;save at storage address
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setb ea ;turn back on interrupts
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lcall get_and_decr_stack_pointer ;get data stack ptr
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;parameter data struct
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movx a,@dptr ;get low byte of setup
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;parameter data struct
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xch a,b ;save in b reg
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lcall get_and_decr_stack_pointer ;adjust data stack ptr
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movx a,@dptr ;get high byte of setup
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;parameter data struct
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push acc ;save on program stack
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mov dptr,#data_struct ;get storage address
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xch a,b
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movx @dptr,a ;save low byte of setup
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inc dptr
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pop acc
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movx @dptr,a ;save high byte of setup
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ret
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[LISTING FOUR]
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init_emulation_mode(process_VT100_input, (char *) t);
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[LISTING FIVE]
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typedef void(*PTF) (); /* a pointer to a function */
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extern void init_emulation_mode(PTF, char *);
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And the VT100 driver can be installed as follows:
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/* initialize VT100 default parameters */
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cursor.row = cursor.col = 1;
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t->origin = t->addlf = t->keymode = RESET;
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t->kblock = t->insert = t->autowrap = RESET;
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t->keypad = NUMERIC;
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clr_display(); /* clear LINKS display */
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init_emulation_mode(process_VT100_input, (char *) t);
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[LISTING SIX]
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BEFORE
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timer0:
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.
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.
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.
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reti
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AFTER
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timer0:
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.
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.
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.
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jnb in_emul_processor,process_emul ;if the emulation driver
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reti ;is already running, then
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;return from interrupt
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process_emul: ;else call the driver
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clr ea ;shut off interrupts while the
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setb in_emul_processor ;recursion prevention semaphore
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setb ea ;is set
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push dph ;protect all registers that the C code driver
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push dpl ;could possibly use (includes all of bank 3
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push psw ;registers)
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push acc
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push b
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push 18h
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push 19h
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push 1ah
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push 1bh
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push 1ch
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push 1dh
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push 1eh
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push 1fh
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mov dptr,#return_from_emul_processor ;put return from
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push dpl ;emulation driver
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push dph ;on stack
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mov dptr,#emul_processor_address ;put emulation processor
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movx a,@dptr ;driver address on stack
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push acc
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inc dptr
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movx a,@dptr
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push acc
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mov dptr,#data_struct ;get the pointer to any
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movx a,@dptr ;data to be passed to
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mov r2,a ;the C language driver.
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inc dptr ;pointer address is
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movx a,@dptr ;stored in r2 and r3
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mov r3,a
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reti ;calls generic emulation driver
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;(last address on program stack)
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[LISTING SEVEN]
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return_from_emul_processor:
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pop 1fh ; restore stack prior to call to VT100 driver
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pop 1eh
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pop 1dh
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pop 1ch
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pop 1bh
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pop 1ah
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pop 19h
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pop 18h
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pop b
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pop acc
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pop psw
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pop dpl
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pop dph
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clr ea ;reset recursion prevention semaphore
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clr in_emul_processor ;while interrupts are off
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setb ea
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.
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.
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ret ; gets address of next instruction to execute
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; in the routine that had been interrupted by
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; timer 0.
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; address taken off the 8051 stack and the stack
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; pointer is updated
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[LISTING EIGHT]
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char *read_VT100_image(char row, char col, char *string,
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char number_to_read)
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{
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short i;
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char *ptr;
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if(row <= VT100_MAX_ROWS && col <= VT100_MAX_COLS)
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{
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/* calculate number of characters to read on row */
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if((number_to_read + col) > (VT100_MAX_COLS+1))
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number_to_read = (VT100_MAX_COLS+1) - col;
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/* get string start address from global screen array */
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ptr = &screen[row - 1][col - 1];
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/* transfer string to return string array */
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for(i = 0; i < number_to_read; i++;)
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string[i] = *ptr++;
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str[i] = 0; /* terminate string */
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}
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return(string);
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}
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[LISTING NINE]
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void get_cursor_position(TERMINALP t, char *row, char *col)
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{
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/* if cursor origin is relative, then calc row position
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based on scrolling start position, else use global row
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position */
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if(t->origin == SET)*row = cursor.row - begin.scroll + 1;
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else *row = cursor.row;
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*col = cursor.col;
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}
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[LISTING TEN]
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static char screen[24][80]; /* VT100 virtual screen image */
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/* put a space character in each virtual image position */
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static void clr_display()
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{
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short i,j;
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for(j = 0;j < VT100_MAX_ROWS; j++)
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for(i = 0;i < VT100_MAX_COLS; i++)
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screen[j][i]=' ';
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}
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[LISTING ELEVEN]
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static char screen[24][80]; /* VT100 virtual screen image */
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char *current, *next, *last;
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/* put a space character in each virtual image position */
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static void clr_display()
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{
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current = &screen[0][0];
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last = &screen[24 - 1][80 - 1];
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do{
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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}while(current < last);
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}
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[LISTING TWELVE]
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static char screen[24][80]; /* VT100 virtual screen image */
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static short begin_scroll_row, end_scroll_row;
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/* Scroll screen up one row. Last row is blank. */
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static void scroll_up()
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{
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short i,j;
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for(j = (begin_scroll_row-1; j<(end_scroll_row-1); i++)
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for(i = 0;i < VT100_MAX_COLS; i++)
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screen[j][i]=screen[j+1][i];
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for(i = 0;i < VT100_MAX_COLS; screen[j][i] = ' ', i++);
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}
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[LISTING THIRTEEN]
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static char screen[24][80]; /* VT100 virtual screen image */
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static char *current, *next, *last;
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static short begin_scroll_row, end_scroll_row;
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/* Scroll screen up one row. Last row is blank. */
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static void scroll_up()
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{
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current = &screen[begin_scroll_row - 1][0];
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next = current + 80;
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last = &screen[end_scroll_row - 1][0];
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do{
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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*current++ = *next++;
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}while(current < last);
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last += 80;
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do{
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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*current++ = ' ';
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}while(current < last);
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}
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[LISTING FOURTEEN]
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#include "speedc.h"
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#include "vt100.h"
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#include "string.h"
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void exception_handler(char code);
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void main()
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{
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TERMINAL t; /* define VT100 setup parameters */
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char string[21];
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char display_string[23];
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cursor.row = cursor.col = 1; /* globals defined in vt100.h */
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t->origin = t->addlf = t->keymode = 0;
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t->kblock = t->insert = t-> autowrap = 0;
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t->keypad = NUMERIC;
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init_emulation_mode(process_VT100_input, (char *)t); /* prototype in vt100.h */
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/* initialize the first 3 lines on the LINKS terminal display by
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using the special LINKS x function. This function allows the
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user to define distinct display regions on the terminal. The
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nomenclature is as follows:
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D means define a display region which is touch sensitive.
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1,2, or 3 means that the touch sensitive area defined will
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generate transmit that particular ASCII character in the
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key buffer when that touch sensitive area is pressed on
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the LINKS screen. This is also referred to as its name.
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A18; means the touch sensitive display area in row A (first row
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on the LINKS), columns 1-8 (touch display areas have 8
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distinct areas per row). The semicolon means the end of
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the touch display definition, and what follows is the
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message to be displayed in that display area.
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B18; means row B (second row), columns 1-8.
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C18; means row C (third row), columns 1-8.
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*/
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x("D1 A18; ");
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x("D2 B18; ");
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x("D3 C18; ");
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open("98N1",1); /* open LINKS RS232 port with special LINKS
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operating system function */
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/* continuously update LINKS terminal display with the current VT100
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virtual image found in rows 1-3, columns 1-20) using read_VT100_scr
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whose prototype is in vt100.h.
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*/
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do{
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read_VT100_scr(1, 1, string, 20); /* read row 1, cols 1-20 */
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strcpy(display_string, "P1"); /* prefix string with special */
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strcat(display_string, string); /* links P cmd (print to touch */
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x(display_string); /* display area named '1') */
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read_VT100_scr(2, 1, string, 20); /* read row 2, cols 1-20 */
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strcpy(display_string, "P2"); /* prefix string with special */
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strcat(display_string, string); /* links P cmd (print to touch */
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x(display_string); /* display area named '2') */
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read_VT100_scr(3, 1, string, 20); /* read row 3, cols 1-20 */
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strcpy(display_string, "P3"); /* prefix string with special */
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strcat(display_string, string); /* links P cmd (print to touch */
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x(display_string); /* display area named '3') */
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|
||
|
|
}while(-1);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* The exception handler is needed for all LINKS applications to handle
|
||
|
|
special LINKS control functions.
|
||
|
|
*/
|
||
|
|
|
||
|
|
void exception_handler(char code)
|
||
|
|
{
|
||
|
|
if (code == 4)turn_off(); /* detects ON/OFF button pressed,
|
||
|
|
and turns LINKS off via LINKS turn_off */
|
||
|
|
}
|
||
|
|
|