lshift.asm bug

[delta trinity]

Hello

I was looking at the asm source code for the k7 (gmp 4.2.1) mmx lshift.asm, 
and found a bug

In the unroll section, there are 2 lines (lines 271 and 272):

	leal	ifelse(UNROLL_BYTES,256,128) -8(%edx,%eax,2), %edx
	leal	ifelse(UNROLL_BYTES,256,128) (%edi,%eax,2), %edi

and further down, in the unroll loop (line 313)

	deflit(`disp0', eval(-i*CHUNK_COUNT*4 ifelse(UNROLL_BYTES,256,-128)))

which should have been

	leal	ifelse(UNROLL_BYTES,256,-128+8) -8(%edx,%eax,2), %edx
	leal	ifelse(UNROLL_BYTES,256,-128+8) (%edi,%eax,2), %edi
	(note the -120 instead of +128)

and further down, in the unroll loop (line 313)

	deflit(`disp0', eval(-i*CHUNK_COUNT*4 ifelse(UNROLL_BYTES,256,+128-8)))
	(note the +120 instead of -128)

it look like the code have simply been copy&pasted from rshift.asm (which is 
correct for rshift.asm).

>From the code as it is now, if the unrolled loop span 256 bytes of data 
(UNROLL_COUNT=64), this will compile a mix of 1 and 4-bytes offset 'movl' in 
the unrolled loop.  This is bad and will create program fault when run.  
With the corrected code, this will compile all 1-byte offset 'movl'.

It is to note that the default (shipped with GMP 4.2.1) is UNROLL_COUNT=32, 
so this bug is not seen under default conditions.

Regards

Eric

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