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.text
.global _start
.type _start,@function
.stabs "crt0.S",100,0,0,_start
.stabs "int:t(0,1)=r(0,1);-32768;32767;",128,0,0,0
.stabs "_start:F(0,1)",36,0,1,_start
_start:
; R14 always contains memory base address (0)
ldi r14,0
; Set the USER stack pointer.
ldi sp, 0x8000 ; SW
mvtc sp, psw ; psw <- SW
ldi sp, _stack
ldi r0,0 ; zero arguments
ldi r1,0
; Clear the BSS. Do it in two parts for efficiency: longwords first
; for most of it, then the remaining 0 to 3 bytes.
ldi r2, __bss_start ; R2 = start of BSS
ldi r3, _end ; R3 = end of BSS + 1
sub r3, r2 ; R3 = BSS size in bytes
mv r4, r3
srli r4, 2 ; R4 = BSS size in longwords (rounded down)
loop1:
cmpeqi r4, 0 ; more longords to zero out?
brf0t.s endloop1 ; nope
st2w r0, @r2+ ; yep, zero out another longword
subi r4, 1 ; decrement count
bra.l loop1 ; go do some more
endloop1:
and3 r4, r3, 3 ; get no. of remaining BSS bytes to clear
loop2:
cmpeqi r4, 0 ; more bytes to zero out?
brf0t.s endloop2 ; nope
stb r0, @r2 ; yep, zero out another byte
addi r2, 1 ; bump address
subi r4, 1 ; decrement count
bra.s loop2 ; go do some more
endloop2:
; Call main, then stop simulator
bl main
bl exit
stop
.Lstart:
.size _start,.Lstart-_start
.stabs "",36,0,0,.Lstart-_start
.section .stack
_stack: .long 1
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