www.pudn.com > ARM9200_U_BOOT.rar > _udivsi3.s, change:2004-03-22,size:2296b


/* # 1 "libgcc1.S" */ 
@ libgcc1 routines for ARM cpu. 
@ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk) 
dividend	.req	r0 
divisor		.req	r1 
result		.req	r2 
curbit		.req	r3 
/* ip		.req	r12	*/ 
/* sp		.req	r13	*/ 
/* lr		.req	r14	*/ 
/* pc		.req	r15	*/ 
	.text 
	.globl	 __udivsi3 
	.type  __udivsi3       ,function 
	.align	0 
 __udivsi3      : 
	cmp	divisor, #0 
	beq	Ldiv0 
	mov	curbit, #1 
	mov	result, #0 
	cmp	dividend, divisor 
	bcc	Lgot_result 
Loop1: 
	@ Unless the divisor is very big, shift it up in multiples of 
	@ four bits, since this is the amount of unwinding in the main 
	@ division loop.  Continue shifting until the divisor is 
	@ larger than the dividend. 
	cmp	divisor, #0x10000000 
	cmpcc	divisor, dividend 
	movcc	divisor, divisor, lsl #4 
	movcc	curbit, curbit, lsl #4 
	bcc	Loop1 
Lbignum: 
	@ For very big divisors, we must shift it a bit at a time, or 
	@ we will be in danger of overflowing. 
	cmp	divisor, #0x80000000 
	cmpcc	divisor, dividend 
	movcc	divisor, divisor, lsl #1 
	movcc	curbit, curbit, lsl #1 
	bcc	Lbignum 
Loop3: 
	@ Test for possible subtractions, and note which bits 
	@ are done in the result.  On the final pass, this may subtract 
	@ too much from the dividend, but the result will be ok, since the 
	@ "bit" will have been shifted out at the bottom. 
	cmp	dividend, divisor 
	subcs	dividend, dividend, divisor 
	orrcs	result, result, curbit 
	cmp	dividend, divisor, lsr #1 
	subcs	dividend, dividend, divisor, lsr #1 
	orrcs	result, result, curbit, lsr #1 
	cmp	dividend, divisor, lsr #2 
	subcs	dividend, dividend, divisor, lsr #2 
	orrcs	result, result, curbit, lsr #2 
	cmp	dividend, divisor, lsr #3 
	subcs	dividend, dividend, divisor, lsr #3 
	orrcs	result, result, curbit, lsr #3 
	cmp	dividend, #0			@ Early termination? 
	movnes	curbit, curbit, lsr #4		@ No, any more bits to do? 
	movne	divisor, divisor, lsr #4 
	bne	Loop3 
Lgot_result: 
	mov	r0, result 
	mov 	pc, lr 
Ldiv0: 
	str	lr, [sp, #-4]! 
	bl	 __div0       (PLT) 
	mov	r0, #0			@ about as wrong as it could be 
	ldmia	sp!, {pc} 
	.size  __udivsi3       , .