Switch to assembler for cputc implementation.

2014-11-22 01:07:55 +01:00
parent 5c8cd00dd5
commit 0a6afb59c0
6 changed files with 166 additions and 72 deletions
--- a/libsrc/c1p/cputc.s
+++ b/libsrc/c1p/cputc.s
@@ -0,0 +1,117 @@
+;
+; Ullrich von Bassewitz, 06.08.1998
+;
+; void cputcxy (unsigned char x, unsigned char y, char c);
+; void cputc (char c);
+;
+
+        .export         _cputcxy, _cputc, cputdirect, putchar
+        .export         newline, plot
+        .import         popa, _gotoxy
+
+        .include        "c1p.inc"
+        .include        "extzp.inc"
+
+_cputcxy:
+        pha                     ; Save C
+        jsr     popa            ; Get Y
+        jsr     _gotoxy         ; Set cursor, drop x
+        pla                     ; Restore C
+
+; Plot a character - also used as internal function
+
+_cputc: cmp     #$0A            ; CR?
+        bne     L1
+        lda     #0
+        sta     CURS_X
+        beq     plot            ; Recalculate pointers
+
+L1:     cmp     #$0D            ; LF?
+        beq     newline         ; Recalculate pointers
+
+; Printable char of some sort
+
+;        cmp     #' '
+;        bcc     cputdirect      ; Other control char < 0x20
+;        tay
+;        bmi     L10
+;        cmp     #$60
+;        bcc     L2
+;        and     #$DF
+;        bne     cputdirect      ; Branch always
+;L2:     and     #$3F
+
+cputdirect:
+        jsr     putchar         ; Write the character to the screen
+
+; Advance cursor position
+
+advance:
+        cpy     SCR_LINELEN     ; xsize-1
+        bne     L3
+        jsr     newline         ; new line
+        ldy     #$FF            ; + cr
+L3:     iny
+        sty     CURS_X
+        rts
+
+newline:
+        lda     SCR_LINELEN     ; xsize-1
+        sec                     ; Account for -1 above
+        adc     SCREEN_PTR
+        sta     SCREEN_PTR
+        bcc     L4
+        inc     SCREEN_PTR+1
+L4:     inc     CURS_Y
+        rts
+
+; Handle character if high bit set
+
+; L10:    and     #$7F
+;        cmp     #$7E            ; PI?
+;        bne     L11
+;        lda     #$5E            ; Load screen code for PI
+;        bne     cputdirect
+; L11:    ora     #$40
+;        bne     cputdirect
+
+
+
+; Set cursor position, calculate RAM pointers
+
+plot:   ldy     CURS_Y
+        lda     ScrLo,y
+        sta     SCREEN_PTR
+        lda     ScrHi,y
+;        ldy     SCR_LINELEN
+;        cpy     #40+1
+;        bcc     @L1
+;        asl     SCREEN_PTR              ; 80 column mode
+;        rol     a
+;@L1:    ora     #$80                    ; Screen at $8000
+        sta     SCREEN_PTR+1
+        rts
+
+
+; Write one character to the screen without doing anything else, return X
+; position in Y
+
+putchar:
+;        ora     RVS             ; Set revers bit
+        ldy     CURS_X
+        sta     (SCREEN_PTR),y  ; Set char
+        rts
+
+; Screen address tables - offset to real screen
+
+.rodata
+
+ScrLo:  .byte   $83, $A3, $C3, $E3, $03, $23, $43, $63
+        .byte   $83, $A3, $C3, $E3, $03, $23, $43, $63
+        .byte   $83, $A3, $C3, $E3, $03, $23, $43, $63
+        .byte   $83
+
+ScrHi:  .byte   $D0, $D0, $D0, $D0, $D1, $D1, $D1, $D1
+        .byte   $D1, $D1, $D1, $D1, $D2, $D2, $D2, $D2
+        .byte   $D2, $D2, $D2, $D2, $D3, $D3, $D3, $D3
+        .byte   $D3