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Fix scale_float for large factors on x86. 

The routine scale_float(cl_LF, cl_I) in file cl_LF_scale_I.cc had not
been adapted to 64-bit exponents on systems where uintD is 32 bit.

Reported by Michael Miller <millermj@lemoyne.edu>.
master
Richard Kreckel 14 years ago
parent
b338e09d3b
commit
9b55b28892
1 changed files with 21 additions and 51 deletions
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  1. 72
      src/float/lfloat/elem/cl_LF_scale_I.cc

72
src/float/lfloat/elem/cl_LF_scale_I.cc
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@ -27,7 +27,7 @@ const cl_LF scale_float (const cl_LF& x, const cl_I& delta)
var uintE uexp = TheLfloat(x)->expo;
if (uexp==0) { return x; }
var uintE udelta;
// |delta| muß <= LF_exp_high-LF_exp_low < 2^32 sein. Wie bei I_to_UL:
// |delta| muß <= LF_exp_high-LF_exp_low < 2^intEsize sein.
if (fixnump(delta)) {
// Fixnum
var sintV sdelta = FN_to_V(delta);
@ -36,55 +36,25 @@ const cl_LF scale_float (const cl_LF& x, const cl_I& delta)
else
{ udelta = sdelta; goto neg; }
} else {
// Bignum
var cl_heap_bignum* bn = TheBignum(delta);
if ((sintD)mspref(arrayMSDptr(bn->data,bn->length),0) >= 0) {
#define IF_LENGTH(i) \
if (bn_minlength <= i) /* genau i Digits überhaupt möglich? */\
if (bn->length == i) /* genau i Digits? */ \
/* 2^((i-1)*intDsize-1) <= delta < 2^(i*intDsize-1) */ \
if ( (i*intDsize-1 > 32) \
&& ( ((i-1)*intDsize-1 >= 32) \
|| (mspref(arrayMSDptr(bn->data,i),0) >= (uintD)bitc(32-(i-1)*intDsize)) \
) ) \
goto overflow; \
else
IF_LENGTH(1)
{ udelta = get_uint1D_Dptr(arrayLSDptr(bn->data,1)); goto pos; }
IF_LENGTH(2)
{ udelta = get_uint2D_Dptr(arrayLSDptr(bn->data,2)); goto pos; }
IF_LENGTH(3)
{ udelta = get_uint3D_Dptr(arrayLSDptr(bn->data,3)); goto pos; }
IF_LENGTH(4)
{ udelta = get_uint4D_Dptr(arrayLSDptr(bn->data,4)); goto pos; }
IF_LENGTH(5)
{ udelta = get_uint4D_Dptr(arrayLSDptr(bn->data,5)); goto pos; }
#undef IF_LENGTH
goto overflow; // delta zu groß
} else {
#define IF_LENGTH(i) \
if (bn_minlength <= i) /* genau i Digits überhaupt möglich? */\
if (bn->length == i) /* genau i Digits? */ \
/* - 2^((i-1)*intDsize-1) > delta >= - 2^(i*intDsize-1) */\
if ( (i*intDsize-1 > 32) \
&& ( ((i-1)*intDsize-1 >= 32) \
|| (mspref(arrayMSDptr(bn->data,i),0) < (uintD)(-bitc(32-(i-1)*intDsize))) \
) ) \
goto underflow; \
else
IF_LENGTH(1)
{ udelta = get_sint1D_Dptr(arrayLSDptr(bn->data,1)); goto pos; }
IF_LENGTH(2)
{ udelta = get_sint2D_Dptr(arrayLSDptr(bn->data,2)); goto pos; }
IF_LENGTH(3)
{ udelta = get_sint3D_Dptr(arrayLSDptr(bn->data,3)); goto pos; }
IF_LENGTH(4)
{ udelta = get_sint4D_Dptr(arrayLSDptr(bn->data,4)); goto pos; }
IF_LENGTH(5)
{ udelta = get_sint4D_Dptr(arrayLSDptr(bn->data,5)); goto pos; }
#undef IF_LENGTH
goto underflow; // delta zu klein
}
// Bignum
var cl_heap_bignum* bn = TheBignum(delta);
if ((sintD)mspref(arrayMSDptr(bn->data,bn->length),0) >= 0) {
// delta >= 0
try {
udelta = cl_I_to_UE(delta);
goto pos;
} catch (const runtime_exception&) {
goto overflow;
}
} else {
// delta < 0
try {
udelta = cl_I_to_E(delta);
goto neg;
} catch (const runtime_exception&) {
goto underflow;
}
}
}
pos: // udelta = delta >=0
@ -95,7 +65,7 @@ const cl_LF scale_float (const cl_LF& x, const cl_I& delta)
{ throw floating_point_overflow_exception(); }
goto ok;
neg: // delta <0, udelta = 2^32+delta
neg: // delta <0, udelta = 2^intEsize+delta
if ( ((uexp = uexp+udelta) >= udelta) // oder Exponent-Unterlauf?
|| (uexp < LF_exp_low) // oder Exponent zu klein?
)

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