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x86/x64: Fix math.ceil(-0.9) result sign.

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Reported by minoki.
This commit is contained in:
Mike Pall 2022-07-08 14:57:01 +02:00
parent 2e98c3d064
commit 674afcd4e2
1 changed files with 6 additions and 7 deletions
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13
src/vm_x86.dasc
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@ -415,9 +415,6 @@
|.macro sseconst_1, reg, tmp // Synthesize 1.0.
| sseconst_hi reg, tmp, 3ff00000
|.endmacro
|.macro sseconst_m1, reg, tmp // Synthesize -1.0.
| sseconst_hi reg, tmp, bff00000
|.endmacro
|.macro sseconst_2p52, reg, tmp // Synthesize 2^52.
| sseconst_hi reg, tmp, 43300000
|.endmacro
@ -3114,15 +3111,17 @@ static void build_subroutines(BuildCtx *ctx)
| addsd xmm1, xmm3 // (|x| + 2^52) - 2^52
| subsd xmm1, xmm3
| orpd xmm1, xmm2 // Merge sign bit back in.
| sseconst_1 xmm3, RDa
| .if mode == 1 // ceil(x)?
| sseconst_m1 xmm2, RDa // Must subtract -1 to preserve -0.
| cmpsd xmm0, xmm1, 6 // x > result?
| andpd xmm0, xmm3
| addsd xmm1, xmm0 // If yes, add 1.
| orpd xmm1, xmm2 // Merge sign bit back in (again).
| .else // floor(x)?
| sseconst_1 xmm2, RDa
| cmpsd xmm0, xmm1, 1 // x < result?
| andpd xmm0, xmm3
| subsd xmm1, xmm0 // If yes, subtract 1.
| .endif
| andpd xmm0, xmm2
| subsd xmm1, xmm0 // If yes, subtract +-1.
|.endif
| movaps xmm0, xmm1
|1: