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strange corner cases: 

(1) zero top 32 bits for 32-bit unsigned ops; 32-bit value can
		be accidentally(?) sign-extended by the compiler/assembler.
	(2) fix return value for mod's that cause traps
This commit is contained in:
cgd 1995-02-25 03:09:32 +00:00
parent 9e15c98955
commit 3f45f31f15
1 changed files with 13 additions and 2 deletions
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15
lib/libc/arch/alpha/gen/divrem.m4
View File

@ -1,4 +1,4 @@
/* $NetBSD: divrem.m4,v 1.1 1995/02/10 17:50:20 cgd Exp $ */
/* $NetBSD: divrem.m4,v 1.2 1995/02/25 03:09:32 cgd Exp $ */
/*
* Copyright (c) 1994, 1995 Carnegie-Mellon University.
@ -84,7 +84,15 @@ LnegB:
/* B is definitely negative, no matter how we got here. */
subq zero, B, B
Ldoit:
')
', `
ifelse(WORDSIZE, `32', `
/*
* Clear the top 32 bits of each operand, as the compiler may
* have sign extended them, if the 31st bit was set.
*/
zap A, 0xf0, A
zap B, 0xf0, B
')' )
/* kill the special cases. */
beq B, Ldotrap /* division by zero! XXX */
@ -164,6 +172,9 @@ ifelse(S, `true',
Ldotrap:
CONST(-2, a0) /* This is the signal to SIGFPE! */
call_pal PAL_gentrap
ifelse(OP, `div',
`', ` mov zero, A /* so that zero will be returned */
')
br zero, Lret_result
END(NAME)