attempt at building a cd image (failed)

[psx_test1] / src / startup.S

diff --git a/src/startup.S b/src/startup.S
index 3df6b83..afce04b 100644 (file)
--- a/src/startup.S
+++ b/src/startup.S
@@ -14,8 +14,7 @@ _start:
        lui a0, REG_BASE
 
        # setup screen mode
-       li t0, 0
-       sw t0, REG_GP1(a0)      # GP1 0: reset
+       sw zero, REG_GP1(a0)    # GP1 0: reset
 
        li t0, 0x03000000       # GP1 3: display enable
        sw t0, REG_GP1(a0)
@@ -38,25 +37,24 @@ _start:
        # clear screen
        li t0, 0x02302010       # cmd 2: fill area (BBGGRR)
        sw t0, REG_GP0(a0)
-       li t0, 0
-       sw t0, REG_GP0(a0)      # ... top left 0,0 (YYYYXXXX)
+       sw zero, REG_GP0(a0)    # ... top left 0,0 (YYYYXXXX)
        li t0, 0x00ef013f       # ... size 319x239 (HHHHWWWW)
        sw t0, REG_GP0(a0)
 
        # draw gouraud triangle
-       li t0, 0x30ff0000
+       li t0, 0x30ff0000       # cmd 30: draw gouraud triangle (+BBGGRR vert0)
        sw t0, REG_GP0(a0)
-       li t0, 160 | (16 << 16)
+       li t0, 160 | (16 << 16) # ... vertex(160, 16)
        sw t0, REG_GP0(a0)
 
-       li t0, 0x0000ff00
+       li t0, 0x0000ff00       # ... color vert1
        sw t0, REG_GP0(a0)
-       li t0, 32 | (180 << 16)
+       li t0, 32 | (180 << 16) # ... vertex(32, 180)
        sw t0, REG_GP0(a0)
 
-       li t0, 0x000000ff
+       li t0, 0x000000ff       # ... color vert2
        sw t0, REG_GP0(a0)
-       li t0, 280 | (220 << 16)
+       li t0, 280 | (220 << 16) # ... vertex(220, 280)
        sw t0, REG_GP0(a0)
 
        #jal main