/ bimulbb.s (emx+gcc) -- Copyright (c) 1996 by Eberhard Mattes #include .globl __bi_mul_bb #define n 0 #define v 4 / int _bi_mul_bb (_bi_bigint *dst, int dst_words, / const _bi_bigint *src1, const _bi_bigint *src2) #define dst 8(%ebp) #define dst_words 12(%ebp) #define src1 16(%ebp) #define src2 20(%ebp) #define n1 -4(%ebp) #define n2 -8(%ebp) #define dn -12(%ebp) #define v1 -16(%ebp) #define v2 -20(%ebp) #define dv -24(%ebp) #define factor -28(%ebp) .text __bi_mul_bb: pushl %ebp movl %esp, %ebp PROFILE_FRAME subl $28, %esp pushl %ebx pushl %esi pushl %edi movl dst, %edi movl src1, %esi /* ESI := src1 */ movl src2, %ebx /* EBX := src2 */ movl n(%esi), %ecx /* ECX := src1->n */ movl n(%ebx), %eax /* EAX := src2->n */ /* Set dst to zero if either src1 or src2 point to zero. The code below does not work if the word count of either factor is zero. */ testl %ecx, %ecx /* src1->n == 0? */ jz Lzero testl %eax, %eax /* src2->n == 0? */ jz Lzero movl %ecx, n1 /* n1 := src1->n */ movl %eax, n2 /* n2 := src2->n */ addl %eax, %ecx cmpl dst_words, %ecx ja Loverflow movl v(%esi), %eax movl v(%ebx), %edx movl %eax, v1 /* v1 := src1->v */ movl %edx, v2 /* v2 := src2->v */ movl %ecx, dn /* dn := src1->n + src2->n */ movl v(%edi), %edi xorl %eax, %eax movl %edi, dv /* dv := dst->v */ rep stosl /* Outer loop, over words of src2. */ ALIGN L1: movl dv, %edi /* EDI := &dst->v[i] */ movl v1, %esi /* ESI := &src1->v[0] */ movl v2, %eax movl n1, %ecx movl (%eax), %edx movl %edx, factor /* factor := src2->v[i] */ xorl %ebx, %ebx /* carry := 0 */ /* Inner loop, over words of src1. */ ALIGN L2: movl (%esi), %eax mull factor addl $4, %esi addl %ebx, %eax adcl $0, %edx addl %eax, (%edi) leal 4(%edi), %edi adcl $0, %edx decl %ecx movl %edx, %ebx jnz L2 /* Handle carry (EBX). */ test %ebx, %ebx jz Lnext add %ebx, (%edi) leal 4(%edi), %edi /* Handle carry (CY). */ jnc Lnext ALIGN L3: add $1, (%edi) leal 4(%edi), %edi jc L3 /* End of outer loop. */ ALIGN Lnext: addl $4, v2 addl $4, dv decl n2 jnz L1 /* Normalize product. Note that dn is non-zero. */ movl dst, %edi movl dn, %eax movl v(%edi), %esi cmpl $1, -4(%esi,%eax,4) sbbl $0, %eax /* Decr EAX if dst->v[dn-1] == 0 */ movl %eax, n(%edi) ALIGN Ldone: xorl %eax, %eax ALIGN Lreturn: popl %edi popl %esi popl %ebx leave EPILOGUE(_bi_mul_bb) ALIGN Loverflow: movl $1, %eax jmp Lreturn ALIGN Lzero: movl $0, n(%edi) jmp Ldone