1.8. PRINTF() WITH SEVERAL ARGUMENTS
Non-optimizing GCC 4.4.5
Non-optimizing GCC is more verbose:
Listing 1.56: Non-optimizing GCC 4.4.5 (assembly output)$LC0:
.ascii "a=%d; b=%d; c=%d\000"
main:
; function prologue:
addiu $sp,$sp,-32
sw $31,28($sp)
sw $fp,24($sp)
move $fp,$sp
lui $28,%hi(gnu_local_gp)
addiu $28,$28,%lo(gnu_local_gp)
; load address of the text string:
lui $2,%hi($LC0)
addiu $2,$2,%lo($LC0)
; set 1st argument of printf():
move $4,$2
; set 2nd argument of printf():
li $5,1 # 0x1
; set 3rd argument of printf():
li $6,2 # 0x2
; set 4th argument of printf():
li $7,3 # 0x3
; get address of printf():
lw $2,%call16(printf)($28)
nop
; call printf():
move $25,$2
jalr $25
nop
; function epilogue:
lw $28,16($fp)
; set return value to 0:
move $2,$0
move $sp,$fp
lw $31,28($sp)
lw $fp,24($sp)
addiu $sp,$sp,32
; return
j $31
nop
Listing 1.57: Non-optimizing GCC 4.4.5 (IDA).text:00000000 main:
.text:00000000
.text:00000000 var_10 = -0x10
.text:00000000 var_8 = -8
.text:00000000 var_4 = -4
.text:00000000
; function prologue:
.text:00000000 addiu $sp, -0x20
.text:00000004 sw $ra, 0x20+var_4($sp)
.text:00000008 sw $fp, 0x20+var_8($sp)
.text:0000000C move $fp, $sp
.text:00000010 la $gp, __gnu_local_gp
.text:00000018 sw $gp, 0x20+var_10($sp)
; load address of the text string:
.text:0000001C la $v0, aADBDCD # "a=%d; b=%d; c=%d"
; set 1st argument of printf():
.text:00000024 move $a0, $v0
; set 2nd argument of printf():
.text:00000028 li $a1, 1
; set 3rd argument of printf():
.text:0000002C li $a2, 2