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In the division core: if the highest bit of the dividend is set, 

we have to be careful when shifting the divisor. Test this.

This fixes PR 7760 by Richard Earnshaw.
This commit is contained in:
is 1999-09-16 09:15:05 +00:00
parent 7f5f4a3af3
commit bc086d24af
1 changed files with 84 additions and 1 deletions
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85
lib/libc/arch/arm32/gen/divsi3.S
View File

@ -1,4 +1,4 @@
/* $NetBSD: divsi3.S,v 1.2 1997/10/17 18:43:48 mark Exp $ */
/* $NetBSD: divsi3.S,v 1.3 1999/09/16 09:15:05 is Exp $ */
/*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
@ -77,6 +77,87 @@ L_divide_l1:
mov r2, #1
mov r3, #0
/*
* If the highest bit of the dividend is set, we have to be
* careful when shifting the divisor. Test this.
*/
movs r1,r1
bpl L_old_code
/*
* At this point, the highest bit of r1 is known to be set.
* We abuse this below in the tst instructions.
*/
tst r1, r0 /*, lsl #0 */
bmi L_divide_b1
tst r1, r0, lsl #1
bmi L_divide_b2
tst r1, r0, lsl #2
bmi L_divide_b3
tst r1, r0, lsl #3
bmi L_divide_b4
tst r1, r0, lsl #4
bmi L_divide_b5
tst r1, r0, lsl #5
bmi L_divide_b6
tst r1, r0, lsl #6
bmi L_divide_b7
tst r1, r0, lsl #7
bmi L_divide_b8
tst r1, r0, lsl #8
bmi L_divide_b9
tst r1, r0, lsl #9
bmi L_divide_b10
tst r1, r0, lsl #10
bmi L_divide_b11
tst r1, r0, lsl #11
bmi L_divide_b12
tst r1, r0, lsl #12
bmi L_divide_b13
tst r1, r0, lsl #13
bmi L_divide_b14
tst r1, r0, lsl #14
bmi L_divide_b15
tst r1, r0, lsl #15
bmi L_divide_b16
tst r1, r0, lsl #16
bmi L_divide_b17
tst r1, r0, lsl #17
bmi L_divide_b18
tst r1, r0, lsl #18
bmi L_divide_b19
tst r1, r0, lsl #19
bmi L_divide_b20
tst r1, r0, lsl #20
bmi L_divide_b21
tst r1, r0, lsl #21
bmi L_divide_b22
tst r1, r0, lsl #22
bmi L_divide_b23
tst r1, r0, lsl #23
bmi L_divide_b24
tst r1, r0, lsl #24
bmi L_divide_b25
tst r1, r0, lsl #25
bmi L_divide_b26
tst r1, r0, lsl #26
bmi L_divide_b27
tst r1, r0, lsl #27
bmi L_divide_b28
tst r1, r0, lsl #28
bmi L_divide_b29
tst r1, r0, lsl #29
bmi L_divide_b30
tst r1, r0, lsl #30
bmi L_divide_b31
/*
* instead of:
* tst r1, r0, lsl #31
* bmi L_divide_b32
*/
b L_divide_b32
L_old_code:
cmp r1, r0
bcc L_divide_b0
cmp r1, r0, lsl #1
@ -139,9 +220,11 @@ L_divide_l1:
bcc L_divide_b29
cmp r1, r0, lsl #30
bcc L_divide_b30
L_divide_b32:
cmp r1, r0, lsl #31
subhs r1, r1,r0, lsl #31
addhs r3, r3,r2, lsl #31
L_divide_b31:
cmp r1, r0, lsl #30
subhs r1, r1,r0, lsl #30
addhs r3, r3,r2, lsl #30