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| author | jvdelisle <jvdelisle@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-05-19 01:04:03 +0000 |
|---|---|---|
| committer | jvdelisle <jvdelisle@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-05-19 01:04:03 +0000 |
| commit | 7bbd7ad5d16a249bdaf58fcf7ea8294b42127f19 (patch) | |
| tree | e363e48aa8385b05ad91d014553d9aa4d1ea607d /libgfortran/intrinsics/ishftc.c | |
| parent | f3b7c9728561b3c7ed58d99979d769ea3d933343 (diff) | |
| download | ppe42-gcc-7bbd7ad5d16a249bdaf58fcf7ea8294b42127f19.tar.gz ppe42-gcc-7bbd7ad5d16a249bdaf58fcf7ea8294b42127f19.zip | |
2007-05-18 Jerry DeLisle <jvdelisle@gcc.gnu.org>
PR libfortran/31964
* intrinsics/ishftc.c (ishftc4, ishftc8, ishftc16): Fix mask to handle
shift of bit-size number of bits.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@124846 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'libgfortran/intrinsics/ishftc.c')
| -rw-r--r-- | libgfortran/intrinsics/ishftc.c | 42 |
1 files changed, 27 insertions, 15 deletions
diff --git a/libgfortran/intrinsics/ishftc.c b/libgfortran/intrinsics/ishftc.c index a147b968389..68cc4cb82c1 100644 --- a/libgfortran/intrinsics/ishftc.c +++ b/libgfortran/intrinsics/ishftc.c @@ -36,8 +36,7 @@ export_proto(ishftc4); GFC_INTEGER_4 ishftc4 (GFC_INTEGER_4 i, GFC_INTEGER_4 shift, GFC_INTEGER_4 size) { - GFC_INTEGER_4 mask; - GFC_UINTEGER_4 bits; + GFC_UINTEGER_4 mask, bits; if (shift < 0) shift = shift + size; @@ -45,9 +44,14 @@ ishftc4 (GFC_INTEGER_4 i, GFC_INTEGER_4 shift, GFC_INTEGER_4 size) if (shift == 0 || shift == size) return i; - mask = (~(GFC_INTEGER_4)0) << size; - bits = i & ~mask; - return (i & mask) | (bits >> (size - shift)) | ((i << shift) & ~mask); + /* In C, the result of the shift operator is undefined if the right operand + is greater than or equal to the number of bits in the left operand. So we + have to special case it for fortran. */ + mask = ~((size == 32) ? (GFC_UINTEGER_4)0 : (~(GFC_UINTEGER_4)0 << size)); + + bits = i & mask; + + return (i & ~mask) | ((bits << shift) & mask) | (bits >> (size - shift)); } extern GFC_INTEGER_8 ishftc8 (GFC_INTEGER_8, GFC_INTEGER_4, GFC_INTEGER_4); @@ -56,8 +60,7 @@ export_proto(ishftc8); GFC_INTEGER_8 ishftc8 (GFC_INTEGER_8 i, GFC_INTEGER_4 shift, GFC_INTEGER_4 size) { - GFC_INTEGER_8 mask; - GFC_UINTEGER_8 bits; + GFC_UINTEGER_8 mask, bits; if (shift < 0) shift = shift + size; @@ -65,9 +68,14 @@ ishftc8 (GFC_INTEGER_8 i, GFC_INTEGER_4 shift, GFC_INTEGER_4 size) if (shift == 0 || shift == size) return i; - mask = (~(GFC_INTEGER_8)0) << size; - bits = i & ~mask; - return (i & mask) | (bits >> (size - shift)) | ((i << shift) & ~mask); + /* In C, the result of the shift operator is undefined if the right operand + is greater than or equal to the number of bits in the left operand. So we + have to special case it for fortran. */ + mask = ~((size == 64) ? (GFC_UINTEGER_8)0 : (~(GFC_UINTEGER_8)0 << size)); + + bits = i & mask; + + return (i & ~mask) | ((bits << shift) & mask) | (bits >> (size - shift)); } #ifdef HAVE_GFC_INTEGER_16 @@ -77,8 +85,7 @@ export_proto(ishftc16); GFC_INTEGER_16 ishftc16 (GFC_INTEGER_16 i, GFC_INTEGER_4 shift, GFC_INTEGER_4 size) { - GFC_INTEGER_16 mask; - GFC_UINTEGER_16 bits; + GFC_UINTEGER_16 mask, bits; if (shift < 0) shift = shift + size; @@ -86,8 +93,13 @@ ishftc16 (GFC_INTEGER_16 i, GFC_INTEGER_4 shift, GFC_INTEGER_4 size) if (shift == 0 || shift == size) return i; - mask = (~(GFC_INTEGER_16)0) << size; - bits = i & ~mask; - return (i & mask) | (bits >> (size - shift)) | ((i << shift) & ~mask); + /* In C, the result of the shift operator is undefined if the right operand + is greater than or equal to the number of bits in the left operand. So we + have to special case it for fortran. */ + mask = ~((size == 128) ? (GFC_UINTEGER_16)0 : (~(GFC_UINTEGER_16)0 << size)); + + bits = i & mask; + + return (i & ~mask) | ((bits << shift) & mask) | (bits >> (size - shift)); } #endif |
