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Diffstat (limited to 'sysdeps/powerpc/q_addsub.c')
| -rw-r--r-- | sysdeps/powerpc/q_addsub.c | 549 |
1 files changed, 0 insertions, 549 deletions
diff --git a/sysdeps/powerpc/q_addsub.c b/sysdeps/powerpc/q_addsub.c deleted file mode 100644 index e4ef6d8..0000000 --- a/sysdeps/powerpc/q_addsub.c +++ /dev/null @@ -1,549 +0,0 @@ -/* Add or subtract two 128-bit floating point values. C prototype. - Copyright (C) 1997 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Library General Public License as - published by the Free Software Foundation; either version 2 of the - License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with the GNU C Library; see the file COPYING.LIB. If not, - write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - -#include <quad_float.h> - -/* Add 'a' to 'b' and put the result in 'result', but treat a[0]=axx, - b[0]=bxx. bxx differs from b[0] only in the high bit, similarly axx. */ -/* Exceptions to raise: - - Invalid (SNaN) - - Invalid (Inf-Inf) - - Overflow - - Underflow - - Inexact - */ - -/* Handle cases where exponent of a or b is maximum. */ -static void -handle_max_exponent(unsigned result[4], - const unsigned a[4], const unsigned b[4], - const unsigned axx, /* Treat as a[0]. */ - const unsigned bxx, /* Treat as b[0]. */ - const unsigned ax, /* axx >> 16 & 0x7fff. */ - const unsigned bx) /* bxx >> 16 & 0x7fff. */ -{ - int ax_ismax, bx_ismax; - unsigned a1,a2,a3, b1,b2,b3; - int a_zeromant, b_zeromant; - - ax_ismax = ax == 0x7fff; - bx_ismax = bx == 0x7fff; - - assert(ax_ismax || bx_ismax); - - a1 = a[1]; a2 = a[2]; a3 = a[3]; - b1 = b[1]; b2 = b[2]; b3 = b[3]; - - a_zeromant = (axx & 0xffff | a1 | a2 | a3) == 0; - b_zeromant = (bxx & 0xffff | b1 | b2 | b3) == 0; - - /* Deal with SNaNs. */ - if ( ax_ismax && !a_zeromant && (axx & 0x8000) == 0 - || bx_ismax && !b_zeromant && (bxx & 0x8000) == 0) - { - set_fpscr_bit(FPSCR_VXSNAN); - axx |= 0x8000; /* Demote the SNaN to a QNaN (whichever of */ - bxx |= 0x8000; /* a or b it was). */ - } - /* Deal with Inf-Inf. */ - else if (a_zeromant && b_zeromant && (axx ^ bxx) == 0x80000000) - { - set_fpscr_bit(FPSCR_VXISI); - bxx |= 0x8000; /* Return an appropriate QNaN. */ - } - - /* Return the lexicographically larger of a or b, ignoring the sign - bits. */ - if ((axx & 0x7fffffff) > (bxx & 0x7fffffff)) goto return_a; - else if ((axx & 0x7fffffff) < (bxx & 0x7fffffff)) goto return_b; - else if (a1 > b1) goto return_a; - else if (a1 < b1) goto return_b; - else if (a2 > b2) goto return_a; - else if (a2 < b2) goto return_b; - else if (a3 > b3) goto return_a; /* I've clearly been writing too */ - else if (a3 < b3) goto return_b; /* much Fortran... */ - - /* If they are equal except for the sign bits, return 'b'. */ - -return_b: - result[0] = bxx; result[1] = b1; result[2] = b2; result[3] = b3; - return; - -return_a: - result[0] = axx; result[1] = a1; result[2] = a2; result[3] = a3; - return; -} - -/* Renormalise and output a FP number. */ -static void -renormalise_value(unsigned result[4], - const unsigned axx, - unsigned ax, - unsigned r0, - unsigned r1, - unsigned r2, - unsigned r3) -{ - int rshift; - if (r0 != 0 || cntlzw(a1) < 16 || 32 > ax-1) - { - rshift = cntlzw(r0)-15 + (-(cntlzw(r0) >> 5) & cntlzw(a1)); - assert(rshift < 32); - if (rshift > ax-1) - { - ax--; - rshift = ax; - } - - result[0] = (axx & 0x80000000 - | ax-rshift << 16 - | r0 << rshift & 0xffff - | a1 >> 32-rshift & 0xffff); - result[1] = a1 << rshift | a2 >> 32-rshift; - result[2] = a2 << rshift | a3 >> 32-rshift; - result[3] = a3 << rshift; - return; - } - result[3] = 0; - /* Special case for zero. */ - if (a1 == 0 && a2 == 0 && a3 == 0) - { - result[0] = axx & 0x80000000; - result[1] = result[2] = 0; - return; - } - while (a1 != 0 && cntlzw(a2) >= 16 && 64 <= ax-1) - { - ax -= 32; - a1 = a2; a2 = a3; a3 = 0; - } - rshift = cntlzw(a1)-15 + (-(cntlzw(a1) >> 5) & cntlzw(a2)); - assert(rshift < 32); - if (rshift > ax-1-32) - { - ax--; - rshift = ax-32; - } - - result[0] = (axx & 0x80000000 - | ax-rshift-32 << 16 - | a1 << rshift & 0xffff - | a2 >> 32-rshift & 0xffff); - result[1] = a2 << rshift | a3 >> 32-rshift; - result[2] = a3 << rshift; - return; -} - -/* Handle the case where one or both numbers are denormalised or zero. - This case almost never happens, so we don't slow the main code - with it. */ -static void -handle_min_exponent(unsigned result[4], - const unsigned a[4], const unsigned b[4], - const unsigned axx, /* Treat as a[0]. */ - const unsigned bxx, /* Treat as b[0]. */ - const unsigned ax, /* axx >> 16 & 0x7fff. */ - const unsigned bx) /* bxx >> 16 & 0x7fff. */ -{ - int ax_denorm, bx_denorm; - unsigned a1,a2,a3, b1,b2,b3; - int a_zeromant, b_zeromant; - - ax_denorm = ax == 0; - bx_denorm = bx == 0; - - assert(ax_denorm || bx_denorm); - - a1 = a[1]; a2 = a[2]; a3 = a[3]; - b1 = b[1]; b2 = b[2]; b3 = b[3]; - - -} - -/* Add a+b+cin modulo 2^32, put result in 'r' and carry in 'cout'. */ -#define addc(r,cout,a,b,cin) \ - do { \ - unsigned long long addc_tmp = (a)+(b)+(cin); - (cout) = addc_tmp >> 32; - (r) = addc_tmp; - } - -/* Calculate a+~b+cin modulo 2^32, put result in 'r' and carry in 'cout'. */ -#define subc(r,cout,a,b,cin) \ - do { \ - unsigned long long addc_tmp = (a)-(b)+(cin)-1; - (cout) = addc_tmp >> 63; - (r) = addc_tmp; - } - -/* Handle the case where both exponents are the same. This requires quite - a different algorithm than the general case. */ -static void -handle_equal_exponents(unsigned result[4], - const unsigned a[4], const unsigned b[4], - const unsigned axx, /* Treat as a[0]. */ - const unsigned bxx, /* Treat as b[0]. */ - unsigned ax) /* [ab]xx >> 16 & 0x7fff. */ -{ - unsigned a1,a2,a3, b1,b2,b3; - int roundmode; - unsigned carry, r0; - - a1 = a[1]; a2 = a[2]; a3 = a[3]; - b1 = b[1]; b2 = b[2]; b3 = b[3]; - - if ((int)(axx ^ bxx) >= 0) - { - int roundmode; - - /* Adding. */ - roundmode = fegetround(); - - /* What about overflow? */ - if (ax == 0x7ffe) - { - /* Oh no! Too big! */ - /* Result: - rounding result - -------- ------ - nearest return Inf with sign of a,b - zero return nearest possible non-Inf value with - sign of a,b - +Inf return +Inf if a,b>0, otherwise return - value just before -Inf. - -Inf return +Inf if a,b>0, otherwise return - value just before -Inf. - */ - set_fpscr_bit(FPSCR_OX); - /* Overflow always produces inexact result. */ - set_fpscr_bit(FPSCR_XX); - - if ( roundmode == FE_TONEAREST - || roundmode == FE_UPWARD && (int)axx >= 0 - || roundmode == FE_DOWNWARD && (int)axx < 0) - { - result[3] = result[2] = result[1] = 0; - result[0] = axx & 0xffff0000 | 0x7fff0000; - } - else - { - result[3] = result[2] = result[1] = 0xffffffff; - result[0] = axx & 0xfffe0000 | 0x7ffeffff; - } - return; - } - - /* We need to worry about rounding/inexact here. Do it like this: */ - if (a3 + b3 & 1) - { - /* Need to round. Upwards? */ - set_fpscr_bit(FPSCR_XX); - carry = ( roundmode == FE_NEAREST && (a3 + b3 & 2) != 0 - || roundmode == FE_UPWARD && (int)axx >= 0 - || roundmode == FE_DOWNWARD && (int)axx < 0); - } - else - carry = 0; /* Result will be exact. */ - - /* Perform the addition. */ - addc(a3,carry,a3,b3,carry); - addc(a2,carry,a2,b2,carry); - addc(a1,carry,a1,b1,carry); - r0 = (axx & 0xffff) + (bxx & 0xffff) + carry; - - /* Shift right by 1. */ - result[3] = a3 >> 1 | a2 << 31; - result[2] = a2 >> 1 | a1 << 31; - result[1] = a1 >> 1 | r0 << 31; - /* Exponent of result is exponent of inputs plus 1. - Sign of result is common sign of inputs. */ - result[0] = r0 >> 1 & 0xffff | axx + 0x10000 & 0xffff0000; - } - else - { - /* Subtracting. */ - - /* Perform the subtraction, a-b. */ - subc(a3,carry,a3,b3,0); - subc(a2,carry,a2,b2,carry); - subc(a1,carry,a1,b1,carry); - subc(r0,carry,a0&0xffff,b0&0xffff,carry); - - /* Maybe we should have calculated b-a... */ - if (carry) - { - subc(a3,carry,0,a3,0); - subc(a2,carry,0,a2,carry); - subc(a1,carry,0,a1,carry); - subc(r0,carry,0,r0,carry); - axx ^= 0x80000000; - } - - renormalise_value(result, axx, ax, r0, a1, a2, a3); - } -} - - -static void -add(unsigned result[4], const unsigned a[4], const unsigned b[4], - unsigned axx, unsigned bxx) -{ - int ax, bx, diff, carry; - unsigned a0,a1,a2,a3, b0,b1,b2,b3,b4, sdiff; - - ax = axx >> 16 & 0x7fff; - bx = bxx >> 16 & 0x7fff; - - /* Deal with NaNs and Inf. */ - if (ax == 0x7fff || bx == 0x7fff) - { - handle_max_exponent(result, a, b, axx, bxx, ax, bx); - return; - } - /* Deal with denorms and zero. */ - if (ax == 0 || bx == 0) - { - handle_min_exponent(result, a, b, axx, bxx, ax, bx); - return; - } - /* Finally, one special case, when both exponents are equal. */ - if (ax == bx) - { - handle_equal_exponents(result, a, b, axx, bxx, ax); - return; - } - - sdiff = axx ^ bxx; - /* Swap a and b if b has a larger magnitude than a, so that a will have - the larger magnitude. */ - if (ax < bx) - { - const unsigned *t; - t = b; b = a; a = t; - diff = bx - ax; - ax = bx; - axx = bxx; - } - else - diff = ax - bx; - - a0 = a[0] & 0xffff | 0x10000; a1 = a[1]; a2 = a[2]; a3 = a[3]; - b0 = b[0] & 0xffff | 0x10000; b1 = b[1]; b2 = b[2]; b3 = b[3]; - if (diff < 32) - { - b4 = b3 << 32-diff; - b3 = b3 >> diff | b2 << 32-biff; - b2 = b2 >> diff | b1 << 32-diff; - b1 = b1 >> diff | b0 << 32-diff; - b0 = b0 >> diff; - } - else if (diff < 64) - { - diff -= 32; - b4 = b3 & 1 | b3 >> (diff == 32) | b2 << 32-biff; - b3 = b2 >> diff | b1 << 32-diff; - b2 = b1 >> diff | b0 << 32-diff; - b1 = b0 >> diff; - b0 = 0; - } - else if (diff < 96) - { - b4 = b2 | b3 | b1 << 32-diff; - b3 = b1 >> diff | b0 << 32-diff; - b2 = b0 >> diff; - b1 = b0 = 0; - } - else if (diff < 128) - { - b4 = b1 | b2 | b3 | b0 << 32-diff; - b3 = b0 >> diff; - b2 = b1 = b0 = 0; - } - else - { - b4 = b0|b1|b2|b3; - b3 = b2 = b1 = b0 = 0; - } - - /* Now, two cases: one for addition, one for subtraction. */ - if ((int)sdiff >= 0) - { - /* Addition. */ - - /* - - /* Perform the addition. */ - addc(a3,carry,a3,b3,0); - addc(a2,carry,a2,b2,carry); - addc(a1,carry,a1,b1,carry); - addc(a0,carry,a0,b0,carry); - - - - if (a0 & 0x20000) - { - /* Need to renormalise by shifting right. */ - /* Shift right by 1. */ - b4 = b4 | a3 << 31; - a3 = a3 >> 1 | a2 << 31; - a2 = a2 >> 1 | a1 << 31; - result[1] = a1 >> 1 | r0 << 31; - /* Exponent of result is exponent of inputs plus 1. - Sign of result is common sign of inputs. */ - result[0] = r0 >> 1 & 0xffff | axx + 0x10000 & 0xffff0000; - } - - - } - else - { - /* Subtraction. */ - - } -} - -/* Add the absolute values of two 128-bit floating point values, - give the result the sign of one of them. The only exception this - can raise is for SNaN. */ -static void -aadd(unsigned result[4], const unsigned a[4], const unsigned b[4]) -{ - unsigned ax, bx, xd; - const unsigned *sml; - unsigned t0,t1,t2,t3,tx, s0,s1,s2,s3,s4, carry; - int rmode, xdelta, shift; - - ax = a[0] >> 16 & 0x7fff; - bx = b[0] >> 16 & 0x7fff; - - /* Deal with . */ - if (ax == 0x7fff) - { - t0 = a[0]; t1 = a[1]; t2 = a[2]; t3 = a[3]; - /* Check for SNaN. */ - if ((t0 & 0x8000) == 0 - && (t0 & 0x7fff | t1 | t2 | t3) != 0) - set_fpscr_bit(FPSCR_VXSNAN); - /* Return b. */ - result[0] = t0; result[1] = t1; result[2] = t2; result[3] = t3; - return; - } - /* Deal with b==Inf or b==NaN. */ - if (bx == 0x7fff) - { - t0 = b[0]; t1 = b[1]; t2 = b[2]; t3 = b[3]; - /* Check for SNaN. */ - if ((t0 & 0x8000) == 0 - && (t0 & 0x7fff | t1 | t2 | t3) != 0) - set_fpscr_bit(FPSCR_VXSNAN); - /* Return b. */ - result[0] = t0; result[1] = t1; result[2] = t2; result[3] = t3; - return; - } - - /* Choose the larger of the two to be 't', and the smaller to be 's'. */ - if (ax > bx) - { - t0 = a[0] & 0xffff | (ax != 0) << 16; - t1 = a[1]; t2 = a[2]; t3 = a[3]; tx = ax; - s0 = b[0] & 0xffff | (bx != 0) << 16; - s1 = b[1]; s2 = b[2]; s3 = b[3]; - xd = ax-bx; - } - else - { - t0 = b[0] & 0xffff | (bx != 0) << 16; - t1 = b[1]; t2 = b[2]; t3 = b[3]; tx = bx; - s0 = a[0] & 0xffff | (ax != 0) << 16; - s1 = a[1]; s2 = a[2]; s3 = a[3]; - sml = a; - xd = bx-ax; - } - - /* Shift 's2' right by 'xd' bits. */ - switch (xd >> 5) - { - case 0: - s4 = 0; - break; - case 1: - s4 = s3; s3 = s2; s2 = s1; s1 = s0; s0 = 0; - break; - case 2: - s4 = s2 | s3 != 0; - s3 = s1; s2 = s0; s1 = s0 = 0; - break; - case 3: - s4 = s1 | (s3|s2) != 0; - s3 = s0; s2 = s1 = s0 = 0; - break; - default: - s4 = s0 | (s3|s2|s1) != 0; - s3 = s2 = s1 = s0 = 0; - } - xd = xd & 0x1f; - if (xd != 0) - { - s4 = s4 >> xd | (s4 << 32-xd) != 0 | s3 << 32-xd; - s3 = s3 >> xd | s2 << 32-xd; - s2 = s2 >> xd | s1 << 32-xd; - s1 = s1 >> xd | s0 << 32-xd; - s0 = s0 >> xd; - } - - /* Do the addition. */ -#define addc(r,cout,a,b,cin) \ - do { \ - unsigned long long addc_tmp = (a)+(b)+(cin); - (cout) = addc_tmp >> 32; - (r) = addc_tmp; - } - addc(t3,carry,t3,s3,0); - addc(t2,carry,t2,s2,carry); - addc(t1,carry,t1,s1,carry); - t0 = t0 + s0 + carry; - - /* Renormalise. */ - xdelta = 15-cntlzw(t0); - if (tx + xdelta <= 0x7fff) - shift = xdelta; - else - { - } -} - -/* Add two 128-bit floating point values. */ -void -__q_add(unsigned result[4], const unsigned a[4], const unsigned b[4]) -{ - if ((a[0] ^ b[0]) >= 0) - aadd(result, a, b); - else - asubtract(result, a, b); -} - -/* Subtract two 128-bit floating point values. */ -void -__q_sub(unsigned result[4], const unsigned a[4], const unsigned b[4]) -{ - if ((a[0] ^ b[0]) < 0) - aadd(result, a, b); - else - asubtract(result, a, b); -} |