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#define VRAMADDR 0x14800000
#define DISPH 480
#define DISPW 800
.globl start
.arm
start:
// r0: y, r1: x
mov r0, #0
mov r1, #0
.Lloopy:
cmp r0, #(DISPH)
beq .Lstop
.Lloopx:
cmp r1, #(DISPW)
bne .Lcontx
mov r1, #0
add r0, #1
b .Lloopy
.Lcontx:
// r2: ((y&0)^(x&0)) ? 0xffffffff : 0
eor r2, r0, r1
and r2, #1
sub r2, #1
// addr: VRAMADDR + (y*DISPW + x)*2
mov r3, #(DISPW)
mul r3, r0
add r3, r1
add r3, r3
add r3, #(VRAMADDR)
// store the pixel
strh r2, [r3]
add r1, #1
b .Lloopx
.Lstop:
b .Lstop
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