git.y1.nz

commit 30149b27201cc779ca7c3de3b622489a9f66641f
parent a89d21e398461c38a29218a9d91885544734522a
Author: Toxa <untoxa@mail.ru>
Date:   Wed,  8 Jun 2022 01:24:20 +0300

SMS/GG: less garbage on screen when clearing VRAM in the initialization code

Diffstat:
M
gbdk-lib/libc/targets/z80/gg/crt0.s
11
++++++++++-
M
gbdk-lib/libc/targets/z80/sms/crt0.s
11
++++++++++-

2 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/gbdk-lib/libc/targets/z80/gg/crt0.s b/gbdk-lib/libc/targets/z80/gg/crt0.s
@@ -98,9 +98,18 @@ _WRITE_VDP_DATA::
 3$:
         ld (#__SYSTEM), a
 
-        call .clear_VRAM
+        ld a, (_shadow_VDP_R1)
+        and #(~.R1_DISP_ON)
+        ld l, a
+        ld h, #(.VDP_REG_MASK | 1)
+        WRITE_VDP_CMD_HL
 
         call _set_default_palette
+        call .clear_VRAM
+
+        ld hl, (_shadow_VDP_R1)
+        ld h, #(.VDP_REG_MASK | 1)
+        WRITE_VDP_CMD_HL
 
         VDP_CANCEL_INT
 
diff --git a/gbdk-lib/libc/targets/z80/sms/crt0.s b/gbdk-lib/libc/targets/z80/sms/crt0.s
@@ -105,9 +105,18 @@ _WRITE_VDP_DATA::
 4$:
         ld (#__SYSTEM), a
 
-        call .clear_VRAM
+        ld a, (_shadow_VDP_R1)
+        and #(~.R1_DISP_ON)
+        ld l, a
+        ld h, #(.VDP_REG_MASK | 1)
+        WRITE_VDP_CMD_HL
 
         call _set_default_palette
+        call .clear_VRAM
+
+        ld hl, (_shadow_VDP_R1)
+        ld h, #(.VDP_REG_MASK | 1)
+        WRITE_VDP_CMD_HL
 
         VDP_CANCEL_INT
 

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