SCREEN_PTR does only contain the offset apparently (unlike on other cbm systems), so we need extra handling

2025-06-25 05:13:09 +02:00
parent 955c6627c0
commit 4db5ac6c14
13 changed files with 356 additions and 36 deletions
--- a/libsrc/mega65/cpeekrevers.s
+++ b/libsrc/mega65/cpeekrevers.s
@@ -0,0 +1,28 @@
+;
+; 2016-02-28, Groepaz
+; 2017-06-15, Greg King
+;
+; unsigned char cpeekrevers (void);
+;
+
+        .include        "mega65.inc"
+
+        .export         _cpeekrevers
+        .importzp       ptr1
+
+_cpeekrevers:
+        lda     SCREEN_PTR + 1
+        clc
+        adc     #>$0800
+        sta     ptr1 + 1
+        lda     SCREEN_PTR
+        sta     ptr1
+
+        ldy     CURS_X
+        lda     (ptr1),y  ; get screen code
+        and     #$80            ; get reverse bit
+        asl     a
+        tax                     ; ldx #>$0000
+        rol     a               ; return boolean value
+
+        rts