diff options
| author | pcpa <paulo.cesar.pereira.de.andrade@gmail.com> | 2012-05-24 15:26:50 -0300 |
|---|---|---|
| committer | Alan Coopersmith <alan.coopersmith@oracle.com> | 2012-05-31 23:00:34 -0700 |
| commit | 63c70c830c79f0b4cfc0f7393662a9cb1169973e (patch) | |
| tree | 9d68dc0b5c22af5da916854627566be8b7d78d48 /lisp/mathimp.c | |
| parent | c110109f1710758d7c87c05720bdff4df316fc7d (diff) | |
Correct 64 bit overflow check and bignum code.
Signed-off-by: pcpa <paulo.cesar.pereira.de.andrade@gmail.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Diffstat (limited to 'lisp/mathimp.c')
| -rw-r--r-- | lisp/mathimp.c | 35 |
1 files changed, 3 insertions, 32 deletions
diff --git a/lisp/mathimp.c b/lisp/mathimp.c index f5c098f..293625b 100644 --- a/lisp/mathimp.c +++ b/lisp/mathimp.c @@ -39,15 +39,6 @@ #define CONST /**/ #endif -/* mask for checking overflow on long operations */ -#ifdef LONG64 -#define FI_MASK 0x4000000000000000L -#define LONGSBITS 63 -#else -#define FI_MASK 0x40000000L -#define LONGSBITS 31 -#endif - #define N_FIXNUM 1 #define N_BIGNUM 2 #define N_FLONUM 3 @@ -2738,7 +2729,7 @@ fi_fi_add_overflow(long op1, long op2) { long op = op1 + op2; - return (op1 > 0 ? op2 > op : op2 < op); + return (op2 >= 0 ? op < op1 : op > op1); } /* @@ -2749,7 +2740,7 @@ fi_fi_sub_overflow(long op1, long op2) { long op = op1 - op2; - return (((op1 < 0) ^ (op2 < 0)) && ((op < 0) ^ (op1 < 0))); + return (op2 >= 0 ? op > op1 : op < op1); } /* @@ -2758,35 +2749,15 @@ fi_fi_sub_overflow(long op1, long op2) static INLINE int fi_fi_mul_overflow(long op1, long op2) { -#ifndef LONG64 - double op = (double)op1 * (double)op2; - - return (op > 2147483647.0 || op < -2147483648.0); -#else - int shift; - long mask; - if (op1 == 0 || op1 == 1 || op2 == 0 || op2 == 1) return (0); - if (op1 == MINSLONG || op2 == MINSLONG) return (1); - if (op1 < 0) op1 = -op1; if (op2 < 0) op2 = -op2; - - for (shift = 0, mask = FI_MASK; shift < LONGSBITS; shift++, mask >>= 1) - if (op1 & mask) - break; - ++shift; - for (mask = FI_MASK; shift < LONGSBITS; shift++, mask >>= 1) - if (op2 & mask) - break; - - return (shift < LONGSBITS); -#endif + return (op1 > MAXSLONG / op2); } |