#include /* * Multiply operation for 32 bit integers. * Input : Operand1 in Reg r5 * Operand2 in Reg r6 * Output: Result [op1 * op2] in Reg r3 */ .text .globl __mulsi3 .type __mulsi3, @function .ent __mulsi3 __mulsi3: .frame r1, 0, r15 add r3, r0, r0 beqi r5, result_is_zero /* multiply by zero */ beqi r6, result_is_zero /* multiply by zero */ bgeid r5, r5_pos xor r4, r5, r6 /* get the sign of the result */ rsubi r5, r5, 0 /* make r5 positive */ r5_pos: bgei r6, r6_pos rsubi r6, r6, 0 /* make r6 positive */ r6_pos: bri l1 l2: add r5, r5, r5 l1: srl r6, r6 addc r7, r0, r0 beqi r7, l2 bneid r6, l2 add r3, r3, r5 blti r4, negateresult rtsd r15, 8 nop negateresult: rtsd r15, 8 rsub r3, r3, r0 result_is_zero: rtsd r15, 8 addi r3, r0, 0 .size __mulsi3, . - __mulsi3 .end __mulsi3