git.y1.nz

commit bbc6375fe33a34a6b5b344101aac44efefc9005b
parent 03613b5550ce741acb1f3307c4f17b9b86115645
Author: Michel Iwaniec <46843052+michel-iwaniec@users.noreply.github.com>
Date:   Tue, 22 Apr 2025 19:01:26 +0100

NES: Fix problem with screen being blank before first vsync() call (#765)

NES: Fix problem with screen being blank before first vsync() call (#765)

- Call .write_shadow_registers_to_buffer at reset, to initialize VBL buffer
Diffstat:
M
gbdk-lib/libc/targets/mos6502/nes/crt0.s
3
+++

1 file changed, 3 insertions(+), 0 deletions(-)
diff --git a/gbdk-lib/libc/targets/mos6502/nes/crt0.s b/gbdk-lib/libc/targets/mos6502/nes/crt0.s
@@ -714,6 +714,9 @@ __crt0_RESET_bankSwitchValue:
     lda #(PPUCTRL_NMI | PPUCTRL_SPR_CHR)
     sta *_shadow_PPUCTRL
     sta PPUCTRL
+    ; Prepare VBL buffer data (need to start at scanline -1 = SCREENHEIGHT-1 for correct Y scroll)
+    ldx #.SCREENHEIGHT-1
+    jsr .write_shadow_registers_to_buffer
     ; Call main
     jsr _main
     ; main finished - loop forever

This webpage is intended to be an accessible preview of this repository. To get a fuller picture, clone it and use the git CLI.