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authordgp <dgp@users.sourceforge.net>2006-03-24 18:20:36 (GMT)
committerdgp <dgp@users.sourceforge.net>2006-03-24 18:20:36 (GMT)
commit27a8d21a8768fc56364cee33b3f3d1a7954248f6 (patch)
treece4fd9f1c5c84359c4aa697db856d29da5478a21 /generic/tclExecute.c
parentb543fbb1683bb82976f50c0a4f7f0c9bf9dd7a70 (diff)
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* generic/tclExecute.c: Revised INST_EXPON implementation to do
calculations in native types as much as possible, moving to mp_ints only when necessary.
Diffstat (limited to 'generic/tclExecute.c')
-rw-r--r--generic/tclExecute.c312
1 files changed, 122 insertions, 190 deletions
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 73b12f6..68078be 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -12,7 +12,7 @@
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclExecute.c,v 1.229 2006/03/24 00:52:07 das Exp $
+ * RCS: @(#) $Id: tclExecute.c,v 1.230 2006/03/24 18:20:37 dgp Exp $
*/
#include "tclInt.h"
@@ -417,11 +417,6 @@ static void ValidatePcAndStackTop(ByteCode *codePtr,
unsigned char *pc, int stackTop,
int stackLowerBound, int checkStack);
#endif /* TCL_COMPILE_DEBUG */
-#if 0
-static Tcl_WideInt ExponWide(Tcl_WideInt w, Tcl_WideInt w2,
- int *errExpon);
-static long ExponLong(long i, long i2, int *errExpon);
-#endif
/*
*----------------------------------------------------------------------
@@ -4566,6 +4561,104 @@ TclExecuteByteCode(
NEXT_INST_F(1, 1, 0);
}
+ /* Following section assumes BIGNUM_AUTO_NARROW */
+ if (*pc == INST_EXPON) {
+ long l2 = 0;
+ int oddExponent = 0, negativeExponent = 0;
+ if (type2 == TCL_NUMBER_LONG) {
+ l2 = *((CONST long *)ptr2);
+ if (l2 == 0) {
+ /* Anything to the zero power is 1 */
+ objResultPtr = eePtr->constants[1];
+ NEXT_INST_F(1, 2, 1);
+ }
+ }
+ switch (type2) {
+ case TCL_NUMBER_LONG: {
+ negativeExponent = (l2 < 0);
+ oddExponent = (l2 & 1);
+ break;
+ }
+#ifndef NO_WIDE_TYPE
+ case TCL_NUMBER_WIDE: {
+ Tcl_WideInt w2 = *((CONST Tcl_WideInt *)ptr2);
+ negativeExponent = (w2 < 0);
+ oddExponent = (w2 & (Tcl_WideInt)1);
+ break;
+ }
+#endif
+ case TCL_NUMBER_BIG: {
+ mp_int big2;
+ if (Tcl_IsShared(value2Ptr)) {
+ Tcl_GetBignumFromObj(NULL, value2Ptr, &big2);
+ } else {
+ Tcl_GetBignumAndClearObj(NULL, value2Ptr, &big2);
+ }
+ negativeExponent = (mp_cmp_d(&big2, 0) == MP_LT);
+ mp_mod_2d(&big2, 1, &big2);
+ oddExponent = !mp_iszero(&big2);
+ mp_clear(&big2);
+ break;
+ }
+ }
+
+ if (negativeExponent) {
+ if (type1 == TCL_NUMBER_LONG) {
+ long l1 = *((CONST long *)ptr1);
+ switch (l1) {
+ case 0:
+ /* zero to a negative power is div by zero error */
+ TRACE(("%s %s => EXPONENT OF ZERO\n", O2S(valuePtr),
+ O2S(value2Ptr)));
+ goto exponOfZero;
+ case -1:
+ if (oddExponent) {
+ TclNewIntObj(objResultPtr, -1);
+ } else {
+ objResultPtr = eePtr->constants[1];
+ }
+ NEXT_INST_F(1, 2, 1);
+ case 1:
+ /* 1 to any power is 1 */
+ objResultPtr = eePtr->constants[1];
+ NEXT_INST_F(1, 2, 1);
+ }
+ }
+ /* Integers with magnitude greater than 1 raise to a negative
+ * power yield the answer zero (see TIP 123) */
+ objResultPtr = eePtr->constants[0];
+ NEXT_INST_F(1, 2, 1);
+ }
+
+ if (type1 == TCL_NUMBER_LONG) {
+ long l1 = *((CONST long *)ptr1);
+ switch (l1) {
+ case 0:
+ /* zero to a positive power is zero */
+ objResultPtr = eePtr->constants[0];
+ NEXT_INST_F(1, 2, 1);
+ case 1:
+ /* 1 to any power is 1 */
+ objResultPtr = eePtr->constants[1];
+ NEXT_INST_F(1, 2, 1);
+ case -1:
+ if (oddExponent) {
+ TclNewIntObj(objResultPtr, -1);
+ } else {
+ objResultPtr = eePtr->constants[1];
+ }
+ NEXT_INST_F(1, 2, 1);
+ }
+ }
+
+ if (type2 != TCL_NUMBER_LONG) {
+ result = TCL_ERROR;
+ Tcl_SetObjResult(interp,
+ Tcl_NewStringObj("exponent too large", -1));
+ goto checkForCatch;
+ }
+ }
+
if ((*pc != INST_MULT)
&& (type1 != TCL_NUMBER_BIG) && (type2 != TCL_NUMBER_BIG)) {
Tcl_WideInt w1, w2, wResult;
@@ -4623,8 +4716,29 @@ TclExecuteByteCode(
}
break;
case INST_EXPON:
- /* TODO: Implement calculation for narrow integer types */
- goto overflow;
+ if (w2 & 1) {
+ wResult = w1;
+ } else {
+ wResult = Tcl_LongAsWide(1);
+ }
+ w1 *= w1;
+ w2 /= 2;
+ for (; w2>Tcl_LongAsWide(1) ; w1*=w1,w2/=2) {
+ if (w1 < 0) {
+ goto overflow;
+ }
+ if (w2 & 1) {
+ wResult *= w1;
+ if (wResult < 0) {
+ goto overflow;
+ }
+ }
+ }
+ wResult *= w1;
+ if (wResult < 0) {
+ goto overflow;
+ }
+ break;
default:
/* Unused, here to silence compiler warning. */
wResult = 0;
@@ -4689,51 +4803,6 @@ TclExecuteByteCode(
mp_clear(&bigRemainder);
break;
case INST_EXPON:
- if (mp_iszero(&big2)) {
- /* Anything to the zero power is 1 */
- mp_clear(&big1);
- mp_clear(&big2);
- objResultPtr = eePtr->constants[1];
- NEXT_INST_F(1, 2, 1);
- }
- if (mp_iszero(&big1)) {
- if (mp_cmp_d(&big2, 0) == MP_LT) {
- TRACE(("%s %s => EXPONENT OF ZERO\n", O2S(valuePtr),
- O2S(value2Ptr)));
- mp_clear(&big1);
- mp_clear(&big2);
- goto exponOfZero;
- }
- mp_clear(&big1);
- mp_clear(&big2);
- objResultPtr = eePtr->constants[0];
- NEXT_INST_F(1, 2, 1);
- }
- if (mp_cmp_d(&big2, 0) == MP_LT) {
- switch (mp_cmp_d(&big1, 1)) {
- case MP_GT:
- objResultPtr = eePtr->constants[0];
- break;
- case MP_EQ:
- objResultPtr = eePtr->constants[1];
- break;
- case MP_LT:
- mp_add_d(&big1, 1, &big1);
- if (mp_cmp_d(&big1, 0) == MP_LT) {
- objResultPtr = eePtr->constants[0];
- break;
- }
- mp_mod_2d(&big2, 1, &big2);
- if (mp_iszero(&big2)) {
- objResultPtr = eePtr->constants[1];
- } else {
- TclNewIntObj(objResultPtr, -1);
- }
- }
- mp_clear(&big1);
- mp_clear(&big2);
- NEXT_INST_F(1, 2, 1);
- }
if (big2.used > 1) {
Tcl_SetObjResult(interp,
Tcl_NewStringObj("exponent too large", -1));
@@ -7313,143 +7382,6 @@ StringForResultCode(
return buf;
}
#endif /* TCL_COMPILE_DEBUG */
-#if 0
-
-/*
- *----------------------------------------------------------------------
- *
- * ExponWide --
- *
- * Procedure to return w**w2 as wide integer
- *
- * Results:
- * Return value is w to the power w2, unless the computation makes no
- * sense mathematically. In that case *errExpon is set to 1.
- *
- * Side effects:
- * None.
- *
- *----------------------------------------------------------------------
- */
-
-static Tcl_WideInt
-ExponWide(
- Tcl_WideInt w, /* The value that must be exponentiated */
- Tcl_WideInt w2, /* The exponent */
- int *errExpon) /* Error code */
-{
- Tcl_WideInt result;
-
- *errExpon = 0;
-
- /*
- * Check for possible errors and simple/edge cases
- */
-
- if (w == 0) {
- if (w2 < 0) {
- *errExpon = 1;
- return W0;
- } else if (w2 > 0) {
- return W0;
- }
- return Tcl_LongAsWide(1); /* By definition and analysis */
- } else if (w < -1) {
- if (w2 < 0) {
- return W0;
- } else if (w2 == 0) {
- return Tcl_LongAsWide(1);
- }
- } else if (w == -1) {
- return (w2 & 1) ? Tcl_LongAsWide(-1) : Tcl_LongAsWide(1);
- } else if ((w == 1) || (w2 == 0)) {
- return Tcl_LongAsWide(1);
- } else if (w>1 && w2<0) {
- return W0;
- }
-
- /*
- * The general case.
- */
-
- result = Tcl_LongAsWide(1);
- for (; w2>Tcl_LongAsWide(1) ; w*=w,w2/=2) {
- if (w2 & 1) {
- result *= w;
- }
- }
- return result * w;
-}
-
-/*
- *----------------------------------------------------------------------
- *
- * ExponLong --
- *
- * Procedure to return i**i2 as long integer
- *
- * Results:
- * Return value is i to the power i2, unless the computation makes no
- * sense mathematically. In that case *errExpon is set to 1.
- *
- * Side effects:
- * None.
- *
- *----------------------------------------------------------------------
- */
-
-static long
-ExponLong(
- long i, /* The value that must be exponentiated */
- long i2, /* The exponent */
- int *errExpon) /* Error code */
-{
- long result;
-
- *errExpon = 0;
-
- /*
- * Check for possible errors and simple cases
- */
-
- if (i == 0) {
- if (i2 < 0) {
- *errExpon = 1;
- return 0L;
- } else if (i2 > 0) {
- return 0L;
- }
- /*
- * By definition and analysis, 0**0 is 1.
- */
- return 1L;
- } else if (i < -1) {
- if (i2 < 0) {
- return 0L;
- } else if (i2 == 0) {
- return 1L;
- }
- } else if (i == -1) {
- return (i2&1) ? -1L : 1L;
- } else if ((i == 1) || (i2 == 0)) {
- return 1L;
- } else if (i > 1 && i2 < 0) {
- return 0L;
- }
-
- /*
- * The general case
- */
-
- result = 1;
- for (; i2>1 ; i*=i,i2/=2) {
- if (i2 & 1) {
- result *= i;
- }
- }
- return result * i;
-}
-#endif
/*
* Local Variables: