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Diffstat (limited to 'sys/lib/libkern/arch/sparc64/divrem.m4')
| -rw-r--r-- | sys/lib/libkern/arch/sparc64/divrem.m4 | 281 |
1 files changed, 0 insertions, 281 deletions
diff --git a/sys/lib/libkern/arch/sparc64/divrem.m4 b/sys/lib/libkern/arch/sparc64/divrem.m4 deleted file mode 100644 index 94c52a0bf96..00000000000 --- a/sys/lib/libkern/arch/sparc64/divrem.m4 +++ /dev/null @@ -1,281 +0,0 @@ -/* $OpenBSD: divrem.m4,v 1.2 2001/08/20 20:15:29 jason Exp $ */ -/* $NetBSD: divrem.m4,v 1.1.1.1 1998/06/20 05:18:14 eeh Exp $ */ - -/* - * Copyright (c) 1992, 1993 - * The Regents of the University of California. All rights reserved. - * - * This software was developed by the Computer Systems Engineering group - * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and - * contributed to Berkeley. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * Header: divrem.m4,v 1.4 92/06/25 13:23:57 torek Exp - */ - -/* - * Division and remainder, from Appendix E of the Sparc Version 8 - * Architecture Manual, with fixes from Gordon Irlam. - */ - -#if defined(LIBC_SCCS) && !defined(lint) -#ifdef notdef - .asciz "@(#)divrem.m4 8.1 (Berkeley) 6/4/93" -#endif - .asciz "$NetBSD: divrem.m4,v 1.1.1.1 1998/06/20 05:18:14 eeh Exp $" -#endif /* LIBC_SCCS and not lint */ - -/* - * Input: dividend and divisor in %o0 and %o1 respectively. - * - * m4 parameters: - * NAME name of function to generate - * OP OP=div => %o0 / %o1; OP=rem => %o0 % %o1 - * S S=true => signed; S=false => unsigned - * - * Algorithm parameters: - * N how many bits per iteration we try to get (4) - * WORDSIZE total number of bits (32) - * - * Derived constants: - * TWOSUPN 2^N, for label generation (m4 exponentiation currently broken) - * TOPBITS number of bits in the top `decade' of a number - * - * Important variables: - * Q the partial quotient under development (initially 0) - * R the remainder so far, initially the dividend - * ITER number of main division loop iterations required; - * equal to ceil(log2(quotient) / N). Note that this - * is the log base (2^N) of the quotient. - * V the current comparand, initially divisor*2^(ITER*N-1) - * - * Cost: - * Current estimate for non-large dividend is - * ceil(log2(quotient) / N) * (10 + 7N/2) + C - * A large dividend is one greater than 2^(31-TOPBITS) and takes a - * different path, as the upper bits of the quotient must be developed - * one bit at a time. - */ - -define(N, `4') -define(TWOSUPN, `16') -define(WORDSIZE, `32') -define(TOPBITS, eval(WORDSIZE - N*((WORDSIZE-1)/N))) - -define(dividend, `%o0') -define(divisor, `%o1') -define(Q, `%o2') -define(R, `%o3') -define(ITER, `%o4') -define(V, `%o5') - -/* m4 reminder: ifelse(a,b,c,d) => if a is b, then c, else d */ -define(T, `%g1') -define(SC, `%g7') -ifelse(S, `true', `define(SIGN, `%g6')') - -/* - * This is the recursive definition for developing quotient digits. - * - * Parameters: - * $1 the current depth, 1 <= $1 <= N - * $2 the current accumulation of quotient bits - * N max depth - * - * We add a new bit to $2 and either recurse or insert the bits in - * the quotient. R, Q, and V are inputs and outputs as defined above; - * the condition codes are expected to reflect the input R, and are - * modified to reflect the output R. - */ -define(DEVELOP_QUOTIENT_BITS, -` ! depth $1, accumulated bits $2 - bl L.$1.eval(TWOSUPN+$2) - srl V,1,V - ! remainder is positive - subcc R,V,R - ifelse($1, N, - ` b 9f - add Q, ($2*2+1), Q - ', ` DEVELOP_QUOTIENT_BITS(incr($1), `eval(2*$2+1)')') -L.$1.eval(TWOSUPN+$2): - ! remainder is negative - addcc R,V,R - ifelse($1, N, - ` b 9f - add Q, ($2*2-1), Q - ', ` DEVELOP_QUOTIENT_BITS(incr($1), `eval(2*$2-1)')') - ifelse($1, 1, `9:')') - -#include "DEFS.h" -#include <machine/trap.h> - -FUNC(NAME) -ifelse(S, `true', -` ! compute sign of result; if neither is negative, no problem - orcc divisor, dividend, %g0 ! either negative? - bge 2f ! no, go do the divide - ifelse(OP, `div', - `xor divisor, dividend, SIGN', - `mov dividend, SIGN') ! compute sign in any case - tst divisor - bge 1f - tst dividend - ! divisor is definitely negative; dividend might also be negative - bge 2f ! if dividend not negative... - neg divisor ! in any case, make divisor nonneg -1: ! dividend is negative, divisor is nonnegative - neg dividend ! make dividend nonnegative -2: -') - ! Ready to divide. Compute size of quotient; scale comparand. - orcc divisor, %g0, V - bnz 1f - mov dividend, R - - ! Divide by zero trap. If it returns, return 0 (about as - ! wrong as possible, but that is what SunOS does...). - t ST_DIV0 - retl - clr %o0 - -1: - cmp R, V ! if divisor exceeds dividend, done - blu Lgot_result ! (and algorithm fails otherwise) - clr Q - sethi %hi(1 << (WORDSIZE - TOPBITS - 1)), T - cmp R, T - blu Lnot_really_big - clr ITER - - ! `Here the dividend is >= 2^(31-N) or so. We must be careful here, - ! as our usual N-at-a-shot divide step will cause overflow and havoc. - ! The number of bits in the result here is N*ITER+SC, where SC <= N. - ! Compute ITER in an unorthodox manner: know we need to shift V into - ! the top decade: so do not even bother to compare to R.' - 1: - cmp V, T - bgeu 3f - mov 1, SC - sll V, N, V - b 1b - inc ITER - - ! Now compute SC. - 2: addcc V, V, V - bcc Lnot_too_big - inc SC - - ! We get here if the divisor overflowed while shifting. - ! This means that R has the high-order bit set. - ! Restore V and subtract from R. - sll T, TOPBITS, T ! high order bit - srl V, 1, V ! rest of V - add V, T, V - b Ldo_single_div - dec SC - - Lnot_too_big: - 3: cmp V, R - blu 2b - nop - be Ldo_single_div - nop - /* NB: these are commented out in the V8-Sparc manual as well */ - /* (I do not understand this) */ - ! V > R: went too far: back up 1 step - ! srl V, 1, V - ! dec SC - ! do single-bit divide steps - ! - ! We have to be careful here. We know that R >= V, so we can do the - ! first divide step without thinking. BUT, the others are conditional, - ! and are only done if R >= 0. Because both R and V may have the high- - ! order bit set in the first step, just falling into the regular - ! division loop will mess up the first time around. - ! So we unroll slightly... - Ldo_single_div: - deccc SC - bl Lend_regular_divide - nop - sub R, V, R - mov 1, Q - b Lend_single_divloop - nop - Lsingle_divloop: - sll Q, 1, Q - bl 1f - srl V, 1, V - ! R >= 0 - sub R, V, R - b 2f - inc Q - 1: ! R < 0 - add R, V, R - dec Q - 2: - Lend_single_divloop: - deccc SC - bge Lsingle_divloop - tst R - b,a Lend_regular_divide - -Lnot_really_big: -1: - sll V, N, V - cmp V, R - bleu 1b - inccc ITER - be Lgot_result - dec ITER - - tst R ! set up for initial iteration -Ldivloop: - sll Q, N, Q - DEVELOP_QUOTIENT_BITS(1, 0) -Lend_regular_divide: - deccc ITER - bge Ldivloop - tst R - bl,a Lgot_result - ! non-restoring fixup here (one instruction only!) -ifelse(OP, `div', -` dec Q -', ` add R, divisor, R -') - -Lgot_result: -ifelse(S, `true', -` ! check to see if answer should be < 0 - tst SIGN - bl,a 1f - ifelse(OP, `div', `neg Q', `neg R') -1:') - retl - ifelse(OP, `div', `mov Q, %o0', `mov R, %o0') |