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| author | sewardj <unknown> | 2001-12-20 15:20:38 +0000 |
|---|---|---|
| committer | sewardj <unknown> | 2001-12-20 15:20:38 +0000 |
| commit | 0cc54eac4ab05b44ddab78d1531ccb9edc5d7e6c (patch) | |
| tree | 978e2f2794544ade93c021607524c8eb3d1d0395 /ghc/compiler/nativeGen/MachMisc.lhs | |
| parent | 5aaf7975d944b50433a15c08e5b9626a78a95227 (diff) | |
| download | haskell-0cc54eac4ab05b44ddab78d1531ccb9edc5d7e6c.tar.gz | |
[project @ 2001-12-20 15:20:37 by sewardj]
Generate floating-point comparisons on x86 which deal with NaNs in what
I assume is an IEEE854 compliant fashion. For
== >= > <= <
if either arg is a NaN, produce False, and for
/=
if either arg is a NaN, produce True.
This is the behaviour that gcc has, by default.
Requires some ultramagical x86 code frags to be emitted. A big comment
in PprMach explains how it works.
Diffstat (limited to 'ghc/compiler/nativeGen/MachMisc.lhs')
| -rw-r--r-- | ghc/compiler/nativeGen/MachMisc.lhs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/ghc/compiler/nativeGen/MachMisc.lhs b/ghc/compiler/nativeGen/MachMisc.lhs index ed5737f524..ee9d934ad2 100644 --- a/ghc/compiler/nativeGen/MachMisc.lhs +++ b/ghc/compiler/nativeGen/MachMisc.lhs @@ -544,7 +544,11 @@ but we don't care, since it doesn't get used much. We hope. | GSUB Size Reg Reg Reg -- src1, src2, dst | GMUL Size Reg Reg Reg -- src1, src2, dst - | GCMP Size Reg Reg -- src1, src2 + -- FP compare. Cond must be `elem` [EQQ, NE, LE, LTT, GE, GTT] + -- Compare src1 with src2; set the Zero flag iff the numbers are + -- comparable and the comparison is True. Subsequent code must + -- test the %eflags zero flag regardless of the supplied Cond. + | GCMP Cond Reg Reg -- src1, src2 | GABS Size Reg Reg -- src, dst | GNEG Size Reg Reg -- src, dst |