implemented conio peek functions for PCE target

2020-07-14 14:22:29 +02:00
parent a4f1e37f0c
commit 1f2fdbd9b1
5 changed files with 143 additions and 2 deletions
--- a/libsrc/pce/cpeekc.s
+++ b/libsrc/pce/cpeekc.s
@@ -0,0 +1,24 @@
+;
+; 2020-07-14, Groepaz
+;
+; char cpeekc (void);
+;
+; get character from current position, do NOT advance cursor
+
+        .export         _cpeekc
+
+        .include        "pce.inc"
+        .include        "extzp.inc"
+
+_cpeekc:
+        st0     #VDC_MARR       ; Memory-Address Read
+        ldy     SCREEN_PTR
+        ldx     SCREEN_PTR+1
+        sty     VDC_DATA_LO
+        stx     VDC_DATA_HI
+
+        st0     #VDC_VRR        ; VRAM Read Register
+        lda     VDC_DATA_LO     ; character
+        and     #<~$80          ; remove reverse bit
+        ldx     #0
+        rts