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Synchronize with fixed libc version: 

If unsigned dividend > INT_MAX, or signed dividend == INT_MIN, be careful
to not overflow the divisor when shifting it to the left.
This commit is contained in:
is 1999-09-17 11:42:56 +00:00
parent 942ecedabb
commit 6cf532dd3d
1 changed files with 87 additions and 2 deletions
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89
sys/lib/libkern/arch/arm32/divsi3.S
View File

@ -1,4 +1,4 @@
/* $NetBSD: divsi3.S,v 1.2 1997/10/17 18:35:19 mark Exp $ */
/* $NetBSD: divsi3.S,v 1.3 1999/09/17 11:42:56 is Exp $ */
/*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
@ -29,7 +29,9 @@ ENTRY(__modsi3)
ldmfd sp!, {pc}
L_overflow:
mvn r0, #0
mov r0, #8 /* SIGFPE */
bl _raise /* raise it */
mov r0, #0
mov pc, lr
ENTRY(__udivsi3)
@ -75,6 +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
@ -137,9 +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