cbm stuff from greggs pull request

2017-12-11 19:49:14 +01:00
parent 947b09ad96
commit 8902730756
21 changed files with 936 additions and 7 deletions
--- a/libsrc/c128/cpeekrevers.s
+++ b/libsrc/c128/cpeekrevers.s
@@ -0,0 +1,51 @@
+;
+; 2016-02-28, Groepaz
+; 2017-06-26, Greg King
+;
+; unsigned char cpeekrevers (void);
+;
+
+        .export         _cpeekrevers
+
+        .include        "zeropage.inc"
+        .include        "c128.inc"
+
+
+_cpeekrevers:
+        lda     MODE
+        bmi     @c80
+
+        ldy     CURS_X
+        lda     (SCREEN_PTR),y  ; get char
+
+@return:
+        and     #$80            ; get reverse flag
+        asl     a
+        tax                     ; ldx #>$0000
+        rol     a               ; return boolean value
+        rts
+
+@c80:
+        lda     SCREEN_PTR
+        ldy     SCREEN_PTR+1
+        clc
+        adc     CURS_X
+        bcc     @s
+        iny
+
+        ; get byte from VDC mem
+@s:     ldx     #VDC_DATA_LO
+        stx     VDC_INDEX
+@L0:    bit     VDC_INDEX
+        bpl     @L0
+        sta     VDC_DATA
+        dex
+        stx     VDC_INDEX
+        sty     VDC_DATA
+
+        ldx     #VDC_RAM_RW
+        stx     VDC_INDEX
+@L1:    bit     VDC_INDEX
+        bpl     @L1             ; wait for blanking
+        lda     VDC_DATA
+        jmp     @return