reassign 130394 gcc-2.95
severity 130394 important
forwarded 130394 [EMAIL PROTECTED]
tags 130394 + patch
tags 130394 + upstream
tags 130394 + fixed
retitle 130394 [PR 5700] [ARM; fixed in 3.0] bug in __umodsi3
thanks
The reason this one didn't show up with a cross-compiler is that the bug
is in the division support routine itself, rather than the compiler
proper.
I haven't tested it yet, but I suspect this patch may fix the problem.
2000-08-22 Nick Clifton <[EMAIL PROTECTED]>
* config/arm/lib1funcs.asm (__umodsi3): Before performing any
restorative additions, test for bottom bits of IP being set,
rather than relying upon the RORs not matching.
(__modsi3): Ditto.
Index: lib1funcs.asm
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/arm/lib1funcs.asm,v
retrieving revision 1.7
diff -u -r1.7 lib1funcs.asm
--- lib1funcs.asm 1999/04/07 13:53:02 1.7
+++ lib1funcs.asm 2002/02/15 14:17:36
@@ -215,6 +215,13 @@
@ then none of the below will match, since the bit in ip will not be
@ in the bottom nibble.
ands overdone, overdone, #0xe0000000
+ @ If we terminated early, because dividend became zero, then the
+ @ bit in ip will not be in the bottom nibble, and we should not
+ @ perform the additions below. We must test for this though
+ @ (rather relying upon the TSTs to prevent the additions) since
+ @ the bit in ip could be in the top two bits which might then match
+ @ with one of the smaller RORs.
+ tstne ip, #0x7
RETc(eq) pc, lr @ No fixups needed
tst overdone, ip, ror #3
addne dividend, dividend, divisor, lsr #3
@@ -397,6 +404,13 @@
@ then none of the below will match, since the bit in ip will not be
@ in the bottom nibble.
ands overdone, overdone, #0xe0000000
+ @ If we terminated early, because dividend became zero, then the
+ @ bit in ip will not be in the bottom nibble, and we should not
+ @ perform the additions below. We must test for this though
+ @ (rather relying upon the TSTs to prevent the additions) since
+ @ the bit in ip could be in the top two bits which might then match
+ @ with one of the smaller RORs.
+ tstne ip, #0x7
beq Lgot_result
tst overdone, ip, ror #3
addne dividend, dividend, divisor, lsr #3
