## ============================================================ ## power.s ## Control Transfer Instructions ## ============================================================ ## ============================================================ .section ".rodata" ## ============================================================ cPrompt1: .asciz "Enter the base: " cPrompt2: .asciz "Enter the exponent: " cScanfFormat: .asciz "%d" cResult: .asciz "%d raised to the %d power is %d.\n" ## ============================================================ .section ".data" ## ============================================================ iPower: .long 1 ## ============================================================ .section ".bss" ## ============================================================ iBase: .skip 4 iExp: .skip 4 iIndex: .skip 4 ## ============================================================ .section ".text" ## ============================================================ ## ------------------------------------------------------------ ## int main(int argc, char *argv[]) ## ## Read a non-negative base and exponent from stdin. Write ## base raised to the exponent power to stdout. ## ## Formal parameter offsets: .equ ARGC, 8 .equ ARGV, 12 ## ------------------------------------------------------------ .globl main .type main,@function main: pushl %ebp movl %esp, %ebp ## printf("Enter the base: "); pushl $cPrompt1 call printf addl $4, %esp ## scanf("%d", &iBase); pushl $iBase pushl $cScanfFormat call scanf addl $8, %esp ## printf("Enter the exponent: "); pushl $cPrompt2 call printf addl $4, %esp ## scanf("%d", &iExp); pushl $iExp pushl $cScanfFormat call scanf addl $8, %esp ## iIndex = 1; movl $1, iIndex loop1: ## if (iIndex > iExp) goto loopend1; movl iIndex, %eax cmpl iExp, %eax jg loopend1 ## iPower *= iBase; movl iPower, %eax imull iBase movl %eax, iPower ## iIndex++; incl iIndex ## goto loop1; jmp loop1 loopend1: ## printf("%d to the %d power is %d.\n", iBase, iExp, iPower); pushl iPower pushl iExp pushl iBase pushl $cResult call printf addl $16, %esp ## return 0; movl $0, %eax movl %ebp, %esp popl %ebp ret