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changeset 7:b898c74f745c
Add console output driver and a greeting message
At basic VDG/SG4 console output driver and handle displaying the greeting
message on colde start or just clearing the screen on a warm start. This
will be replaced by a more capable console driver in a future update.
Note that the console treats CR and LF according to their proper definition
(return carriage and move one line forward). CR, LF, and BS are all
non-destructive. To get a destructive backspace, do "BS SPACE BS". TAB stops
are eight spaces and outputing TAB *is* destructive.
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Fri, 04 Nov 2022 17:10:38 -0600 |
| parents | 80b9b4503bb4 |
| children | 6e8bb5223e6a |
| files | src/lwbasic.s |
| diffstat | 1 files changed, 107 insertions(+), 1 deletions(-) [+] |
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--- a/src/lwbasic.s Fri Nov 04 00:33:38 2022 -0600 +++ b/src/lwbasic.s Fri Nov 04 17:10:38 2022 -0600 @@ -8,6 +8,7 @@ *pragmapush list *pragma nolist *pragma noexpandcond + *pragma cescapes ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Utility macros ; @@ -183,9 +184,11 @@ ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Start of memory which has the direct page and other data. org 0 +dpstart equ * ; start of direct page rmb 0x71-* ; align RSTFLG/RSTVEC for stock ROM compatibility RSTFLG rmb 1 ; 0x55 if RSTVEC is valid RSTVEC rmb 2 ; points to warm start routine (must start with NOP) +console_curptr rmb 2 ; current cursor pointer for console driver rmb 0x100-* ; make sure the stuff that isn't direct page is outside of it SW3VEC rmb 3 ; SWI3 vector (for compatibility) SW2VEC rmb 3 ; SWI2 vector (for compatibility) @@ -328,6 +331,8 @@ blo initc6 ; brif not jmp initc7 ; go back to mainline initc7 lds #textscreen ; reset stack to somewhere safe + lda #0x12 ; activate ROM warm start handler + sta warmstart ldx #INT.FLAG ; point to bounce vector destination ldu #int_init ; point to initializer for bounce vectors ldb #int_inite-int_init ; number of bytes to copy @@ -374,7 +379,108 @@ endc ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; Cold start handling -coldstart +coldstart ldx #dpstart ; point to start of direct page + ldd #0 ; set up for blanking +coldstart0 std ,x++ ; blank a couple of bytes + cmpx #textscreen ; end of low memory? + blo coldstart0 ; brif not + ldx #warmstart ; set up warm start handler + stx RSTVEC + lda #0x55 ; activate warm start handler + sta RSTFLG + ldx #greeting ; display greeting + jsr console_outstr + bra * +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; Warm start handling + ifdef COCO3 +warmstart fcb 0xff ; set to 0xff to force ROM/RAM copy on reset + else +warmstart nop ; flag warm start routine as valid + endc + jsr console_clear ; clear screen + bra * +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; System startup message +; (start with form feed to clear screen; saves 2 bytes over 'jsr console_clear' in cold start) +greeting fcc '\fLWBASIC VERSION 2022.0\r\n' + fcc 'COPYRIGHT (C) 2022 BY LOST\r\n' + fcc 'WIZARD ENTERPRISES INC.\r\n' + fcs '\n' +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +; Console output driver +; +; Clear screen +console_clear ldb #0x60 ; VDG space character + ldx #textscreen ; point to text screen + stx console_curptr ; set cursor pointer to start of screen +console_clear0 stb ,x+ ; blank a character + cmpx #textscreen+0x200 ; end of screen? + blo console_clear0 ; brif not + rts +; Output NUL terminated string +console_outstr0 bsr console_outchr ; output the character +console_outstr lda ,x+ ; get byte from string + bne console_outstr0 ; brif not end of string + rts +; Output a single character to the screen; enter with character in A +console_outchr pshs d,x ; save registers + ldx #console_curptr ; get current cursor pointer + cmpa #0x20 ; printable character? + bne console_outchr5 ; brif not + tsta ; is it a graphics block? + beq console_outchr1 ; brif so - don't do anything to it + cmpa #0x40 ; number or most non-alpha characters? + blo console_outchr0 ; brif so - will need to flip bit 6 + cmpa #0x60 ; upper case? + blo console_outchr1 ; brif so - don't need to do anything to it + anda #0xdf ; clear bit 5 of lower case; moves it to bottom of character set +console_outchr0 eora #0x40 ; flip bit 6 - the "inversion" bit +console_outchr1 sta ,x+ ; stick it on screen +console_outchr2 stx console_curptr ; save new cursor pointer + cmpx #textscreen+0x200 ; end of screen? + blo console_outchr4 ; brif not + leax -32,x ; move pointer back one line + stx console_curptr + ldx #textscreen ; point to start of screen +console_outchr3 ldd 32,x ; get bytes from next line + std ,x++ ; stick them here + cmpx #textscreen+0x1e0 ; at last row? + blo console_outchr3 ; brif not + ldb #0x60 ; space character for VDG screen + bsr console_clear0 ; blank out last row (borrowing screen clear loop) +console_outchr4 puls d,x,pc ; restore registers and return +console_outchr5 cmpa #0x0c ; form feed? + bne console_outchr6 ; brif not + bsr console_clear ; clear screen + puls d,x,pc ; restore registers and return +console_outchr6 cmpa #0x0d ; carriage return? + bne console_outchr7 ; brif not + ldb console_curptr+1 ; get current screen pointer LSB + andb #0xe0 ; reset offset to start of line + stb console_curptr+1 ; save new pointer LSB + puls d,x,pc ; restore registers and return +console_outchr7 cmpa #0x0a ; line feed? + bne console_outchr8 ; brif not + ldx console_curptr ; get cursor pointer + leax 32,x ; move it forward exactly one line + bra console_outchr2 ; go update stuff check for scroll +console_outchr8 cmpa #0x08 ; backspace? + bne console_outchr9 ; brif not + cmpx #textscreen ; at start of screen? + beq console_outchr4 ; brif so - backspace does nothing + leax -1,x ; back up pointer (backspace is non-destructive) + bra console_outchr2 ; go update pointers, etc. +console_outchr9 cmpa #0x09 ; TAB character? + bne console_outchr4 ; brif not + ldb console_curptr ; get LSB of pointer + andb #7 ; 8 space tabs - only keep low 3 bits + lda #0x60 ; space character (tab is destructive) +console_outchra sta ,x+ ; put a space out + incb ; bump counter + cmpb #8 ; at next tab stop? + blo console_outchra ; brif not + bra console_outchr2 ; go update details and check for scroll ifndef COCO3 ; Need to ensure the vectors are at 0xbff2 zmb 0xbff2-* ; pad ROM up to the vector point