X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gas%2Fflonum-mult.c;h=fe7ecc1f31a566eaa77915473c3b84f780e3b31f;hb=bd70b1f240b24d8c9b08868ca777f5a81d13c0c2;hp=b01f93ba94ee262b6760005408bc946b42b804b1;hpb=fecd2382e77b89f12c9d630ed4e42e9a54ba6953;p=deliverable%2Fbinutils-gdb.git diff --git a/gas/flonum-mult.c b/gas/flonum-mult.c index b01f93ba94..fe7ecc1f31 100644 --- a/gas/flonum-mult.c +++ b/gas/flonum-mult.c @@ -1,117 +1,112 @@ -/* flonum_multip.c - multiply two flonums - Copyright (C) 1987, 1990, 1991 Free Software Foundation, Inc. +/* flonum_mult.c - multiply two flonums + Copyright (C) 1987-2020 Free Software Foundation, Inc. -This file is part of Gas, the GNU Assembler. + This file is part of GAS, the GNU Assembler. -The GNU assembler is distributed in the hope that it will be -useful, but WITHOUT ANY WARRANTY. No author or distributor -accepts responsibility to anyone for the consequences of using it -or for whether it serves any particular purpose or works at all, -unless he says so in writing. Refer to the GNU Assembler General -Public License for full details. + GAS is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. -Everyone is granted permission to copy, modify and redistribute -the GNU Assembler, but only under the conditions described in the -GNU Assembler General Public License. A copy of this license is -supposed to have been given to you along with the GNU Assembler -so you can know your rights and responsibilities. It should be -in a file named COPYING. Among other things, the copyright -notice and this notice must be preserved on all copies. */ + GAS 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 General Public + License for more details. -/* static const char rcsid[] = "$Id$"; */ + You should have received a copy of the GNU General Public License + along with GAS; see the file COPYING. If not, write to the Free + Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA + 02110-1301, USA. */ +#include "ansidecl.h" #include "flonum.h" /* plan for a . b => p(roduct) - +-------+-------+-/ /-+-------+-------+ | a | a | ... | a | a | | A | A-1 | | 1 | 0 | +-------+-------+-/ /-+-------+-------+ - +-------+-------+-/ /-+-------+-------+ | b | b | ... | b | b | | B | B-1 | | 1 | 0 | +-------+-------+-/ /-+-------+-------+ - +-------+-------+-/ /-+-------+-/ /-+-------+-------+ | p | p | ... | p | ... | p | p | | A+B+1| A+B | | N | | 1 | 0 | +-------+-------+-/ /-+-------+-/ /-+-------+-------+ - /^\ - (carry) a .b ... | ... a .b a .b - A B | 0 1 0 0 - | - ... | ... a .b - | 1 0 - | - | ... - | - | - | - | ___ - | \ - +----- P = > a .b - N /__ i j - - N = 0 ... A+B - - for all i,j where i+j=N - [i,j integers > 0] - -a[], b[], p[] may not intersect. -Zero length factors signify 0 significant bits: treat as 0.0. -0.0 factors do the right thing. -Zero length product OK. - -I chose the ForTran accent "foo[bar]" instead of the C accent "*garply" -because I felt the ForTran way was more intuitive. The C way would -probably yield better code on most C compilers. Dean Elsner. -(C style also gives deeper insight [to me] ... oh well ...) -*/ + /^\ + (carry) a .b ... | ... a .b a .b + A B | 0 1 0 0 + | + ... | ... a .b + | 1 0 + | + | ... + | + | + | + | ___ + | \ + +----- P = > a .b + N /__ i j + + N = 0 ... A+B + + for all i,j where i+j=N + [i,j integers > 0] + + a[], b[], p[] may not intersect. + Zero length factors signify 0 significant bits: treat as 0.0. + 0.0 factors do the right thing. + Zero length product OK. + + I chose the ForTran accent "foo[bar]" instead of the C accent "*garply" + because I felt the ForTran way was more intuitive. The C way would + probably yield better code on most C compilers. Dean Elsner. + (C style also gives deeper insight [to me] ... oh well ...) */ -void flonum_multip (a, b, product) -const FLONUM_TYPE *a; -const FLONUM_TYPE *b; -FLONUM_TYPE *product; +void +flonum_multip (const FLONUM_TYPE *a, const FLONUM_TYPE *b, + FLONUM_TYPE *product) { - int size_of_a; /* 0 origin */ - int size_of_b; /* 0 origin */ - int size_of_product; /* 0 origin */ - int size_of_sum; /* 0 origin */ - int extra_product_positions;/* 1 origin */ - unsigned long work; - unsigned long carry; - long exponent; - LITTLENUM_TYPE * q; - long significant; /* TRUE when we emit a non-0 littlenum */ - /* ForTran accent follows. */ - int P; /* Scan product low-order -> high. */ - int N; /* As in sum above. */ - int A; /* Which [] of a? */ - int B; /* Which [] of b? */ - - if((a->sign!='-' && a->sign!='+') || (b->sign!='-' && b->sign!='+')) { - /* ... - Got to fail somehow. Any suggestions? */ - product->sign=0; - return; - } - product -> sign = (a->sign == b->sign) ? '+' : '-'; - size_of_a = a -> leader - a -> low; - size_of_b = b -> leader - b -> low; - exponent = a -> exponent + b -> exponent; - size_of_product = product -> high - product -> low; - size_of_sum = size_of_a + size_of_b; - extra_product_positions = size_of_product - size_of_sum; + int size_of_a; /* 0 origin */ + int size_of_b; /* 0 origin */ + int size_of_product; /* 0 origin */ + int size_of_sum; /* 0 origin */ + int extra_product_positions; /* 1 origin */ + unsigned long work; + unsigned long carry; + long exponent; + LITTLENUM_TYPE *q; + long significant; /* TRUE when we emit a non-0 littlenum */ + /* ForTran accent follows. */ + int P; /* Scan product low-order -> high. */ + int N; /* As in sum above. */ + int A; /* Which [] of a? */ + int B; /* Which [] of b? */ + + if ((a->sign != '-' && a->sign != '+') + || (b->sign != '-' && b->sign != '+')) + { + /* Got to fail somehow. Any suggestions? */ + product->sign = 0; + return; + } + product->sign = (a->sign == b->sign) ? '+' : '-'; + size_of_a = a->leader - a->low; + size_of_b = b->leader - b->low; + exponent = a->exponent + b->exponent; + size_of_product = product->high - product->low; + size_of_sum = size_of_a + size_of_b; + extra_product_positions = size_of_product - size_of_sum; if (extra_product_positions < 0) { - P = extra_product_positions; /* P < 0 */ - exponent -= extra_product_positions; /* Increases exponent. */ + P = extra_product_positions; /* P < 0 */ + exponent -= extra_product_positions; /* Increases exponent. */ } else { @@ -119,83 +114,74 @@ FLONUM_TYPE *product; } carry = 0; significant = 0; - for (N = 0; - N <= size_of_sum; - N++) + for (N = 0; N <= size_of_sum; N++) { work = carry; carry = 0; - for (A = 0; - A <= N; - A ++) + for (A = 0; A <= N; A++) { B = N - A; - if (A <= size_of_a && B <= size_of_b && B >= 0) + if (A <= size_of_a && B <= size_of_b && B >= 0) { #ifdef TRACE -printf("a:low[%d.]=%04x b:low[%d.]=%04x work_before=%08x\n", A, a->low[A], B, b->low[B], work); + printf ("a:low[%d.]=%04x b:low[%d.]=%04x work_before=%08x\n", + A, a->low[A], B, b->low[B], work); #endif - work += a -> low [A] * b -> low [B]; + /* Watch out for sign extension! Without the casts, on + the DEC Alpha, the multiplication result is *signed* + int, which gets sign-extended to convert to the + unsigned long! */ + work += (unsigned long) a->low[A] * (unsigned long) b->low[B]; carry += work >> LITTLENUM_NUMBER_OF_BITS; work &= LITTLENUM_MASK; #ifdef TRACE -printf("work=%08x carry=%04x\n", work, carry); + printf ("work=%08x carry=%04x\n", work, carry); #endif } } significant |= work; - if (significant || P<0) + if (significant || P < 0) { if (P >= 0) { - product -> low [P] = work; + product->low[P] = work; #ifdef TRACE -printf("P=%d. work[p]:=%04x\n", P, work); + printf ("P=%d. work[p]:=%04x\n", P, work); #endif } - P ++; + P++; } else { - extra_product_positions ++; - exponent ++; + extra_product_positions++; + exponent++; } } - /* - * [P]-> position # size_of_sum + 1. - * This is where 'carry' should go. - */ + /* [P]-> position # size_of_sum + 1. + This is where 'carry' should go. */ #ifdef TRACE -printf("final carry =%04x\n", carry); + printf ("final carry =%04x\n", carry); #endif if (carry) { if (extra_product_positions > 0) - { - product -> low [P] = carry; - } + product->low[P] = carry; else { - /* No room at high order for carry littlenum. */ - /* Shift right 1 to make room for most significant littlenum. */ - exponent ++; - P --; - for (q = product -> low + P; - q >= product -> low; - q --) + /* No room at high order for carry littlenum. */ + /* Shift right 1 to make room for most significant littlenum. */ + exponent++; + P--; + for (q = product->low + P; q >= product->low; q--) { - work = * q; - * q = carry; + work = *q; + *q = carry; carry = work; } } } else - { - P --; - } - product -> leader = product -> low + P; - product -> exponent = exponent; + P--; + product->leader = product->low + P; + product->exponent = exponent; } - -/* end: flonum_multip.c */