NES complete now (tested and conio test updated), replaces what is in #532

2025-05-24 19:19:49 +02:00
parent 6628c4ff43
commit 228316ff58
6 changed files with 85 additions and 36 deletions
--- a/libsrc/nes/cpeekc.s
+++ b/libsrc/nes/cpeekc.s
@@ -0,0 +1,37 @@
+;
+; 2016-02-28, Groepaz
+; 2017-08-17, Greg King
+;
+; char cpeekc (void);
+;
+
+        .export         _cpeekc
+
+        .import         ppubuf_waitempty
+        .forceimport    initconio
+
+        .include        "nes.inc"
+
+
+_cpeekc:
+        ; wait until all console data has been written
+        jsr     ppubuf_waitempty
+
+        ldy     SCREEN_PTR+1
+        lda     SCREEN_PTR
+
+; waiting for vblank is incredibly slow ://
+vwait:
+;       ldx     PPU_STATUS
+;       bpl     vwait
+
+        ldx     #>$0000
+        sty     PPU_VRAM_ADDR2
+        sta     PPU_VRAM_ADDR2
+        lda     PPU_VRAM_IO     ; first read is invalid
+        lda     PPU_VRAM_IO     ; get data
+        stx     PPU_VRAM_ADDR2
+        stx     PPU_VRAM_ADDR2
+
+        and     #<~$80          ; remove reverse bit
+        rts