vertical wave

[snes_test1] / hwregs.inc

diff --git a/hwregs.inc b/hwregs.inc
index 672aedf..5fd9f2c 100644 (file)
--- a/hwregs.inc
+++ b/hwregs.inc
@@ -82,6 +82,8 @@
        REG_MDMAEN      = $420b
        REG_HDMAEN      = $420c
 
+       REG_HVBJOY      = $4212
+
        REG_DMAP_BASE   = $4300
        REG_BBAD_BASE   = $4301
        REG_A1TL_BASE   = $4302
@@ -123,3 +125,11 @@
        setreg REG_CGDATA, (g >> 3 | b << 2)
        .endmacro
 
+       .macro wait_vblank
+@wait_vblank_loop:
+       lda REG_HVBJOY
+       and #$80
+       beq @wait_vblank_loop
+       .endmacro
+
+       ; vi:ft=asm_ca65: