n_support.S revision 1.9.4.1
1 /* $NetBSD: n_support.S,v 1.9.4.1 2015/05/25 09:05:25 msaitoh Exp $ */ 2 /* 3 * Copyright (c) 1985, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * @(#)support.s 8.1 (Berkeley) 6/4/93 31 */ 32 #include <machine/asm.h> 33 34 WEAK_ALIAS(logbl,logb) 35 WEAK_ALIAS(copysignl, _copysignl) 36 WEAK_ALIAS(_copysignl, copysign) 37 38 .text 39 _sccsid: 40 .asciz "@(#)support.s\t1.3 (Berkeley) 8/21/85; 8.1 (ucb.elefunt) 6/4/93" 41 42 /* 43 * copysign(x,y), 44 * logb(x), 45 * scalb(x,N), 46 * finite(x), 47 * drem(x,y), 48 * Coded in vax assembly language by K.C. Ng, 3/14/85. 49 * Revised by K.C. Ng on 4/9/85. 50 */ 51 52 /* 53 * double copysign(double x,double y) 54 */ 55 56 ENTRY(copysign, 0) 57 movq 4(%ap),%r0 # load x into %r0 58 bicw3 $0x807f,%r0,%r2 # mask off the exponent of x 59 beql Lz # if zero or reserved op then return x 60 bicw3 $0x7fff,12(%ap),%r2 # copy the sign bit of y into %r2 61 bicw2 $0x8000,%r0 # replace x by |x| 62 bisw2 %r2,%r0 # copy the sign bit of y to x 63 Lz: ret 64 65 ENTRY(copysignf, 0) 66 movl 4(%ap),%r0 # load x into %r0 67 bicw3 $0x807f,%r0,%r2 # mask off the exponent of x 68 beql 1f # if zero or reserved op then return x 69 bicw3 $0x7fff,8(%ap),%r2 # copy the sign bit of y into %r2 70 bicw2 $0x8000,%r0 # replace x by |x| 71 bisw2 %r2,%r0 # copy the sign bit of y to x 72 1: ret 73 74 /* 75 * float logbf(float x); 76 */ 77 ENTRY(logbf, 0) 78 cvtfd 4(%ap),-(%sp) 79 calls $2,_C_LABEL(logb) 80 cvtdf %r0,%r0 81 ret 82 83 /* 84 * double logb(double x); 85 */ 86 ENTRY(logb, 0) 87 bicl3 $0xffff807f,4(%ap),%r0 # mask off the exponent of x 88 beql Ln 89 ashl $-7,%r0,%r0 # get the bias exponent 90 subl2 $129,%r0 # get the unbias exponent 91 cvtld %r0,%r0 # return the answer in double 92 ret 93 Ln: movq 4(%ap),%r0 # %r0:1 = x (zero or reserved op) 94 bneq 1f # simply return if reserved op 95 movq $0x0000fe00ffffcfff,%r0 # -2147483647.0 96 1: ret 97 98 /* 99 * long finite(double x); 100 */ 101 #ifndef __GFLOAT__ 102 .globl finitef 103 finitef = finite 104 #endif 105 ENTRY(finite, 0) 106 bicw3 $0x7f,4(%ap),%r0 # mask off the mantissa 107 cmpw %r0,$0x8000 # to see if x is the reserved op 108 beql 1f # if so, return FALSE (0) 109 movl $1,%r0 # else return TRUE (1) 110 ret 111 1: clrl %r0 112 ret 113 114 /* int isnan(double x); 115 */ 116 #if 0 117 ENTRY(isnan, 0) 118 clrl %r0 119 ret 120 #endif 121 122 /* int isnanf(float x); 123 */ 124 ENTRY(isnanf, 0) 125 clrl %r0 126 ret 127 128 /* 129 * double scalb(x,N) 130 * double x; double N; 131 */ 132 .set ERANGE,34 133 134 ENTRY(scalb, 0) 135 movq 4(%ap),%r0 136 bicl3 $0xffff807f,%r0,%r3 137 beql ret1 # 0 or reserved operand 138 movq 12(%ap),%r4 139 cvtdl %r4, %r2 140 cmpl %r2,$0x12c 141 bgeq ovfl 142 cmpl %r2,$-0x12c 143 bleq unfl 144 ashl $7,%r2,%r2 145 addl2 %r2,%r3 146 bleq unfl 147 cmpl %r3,$0x8000 148 bgeq ovfl 149 addl2 %r2,%r0 150 ret 151 ovfl: pushl $ERANGE 152 calls $1,_C_LABEL(infnan) # if it returns 153 bicw3 $0x7fff,4(%ap),%r2 # get the sign of input arg 154 bisw2 %r2,%r0 # re-attach the sign to %r0/1 155 ret 156 unfl: movq $0,%r0 157 ret1: ret 158 159 /* 160 * DREM(X,Y) 161 * RETURN X REM Y =X-N*Y, N=[X/Y] ROUNDED (ROUNDED TO EVEN IN THE HALF WAY CASE) 162 * DOUBLE PRECISION (VAX D format 56 bits) 163 * CODED IN VAX ASSEMBLY LANGUAGE BY K.C. NG, 4/8/85. 164 */ 165 .set EDOM,33 166 167 ENTRY(drem, 0x0fc0) 168 subl2 $12,%sp 169 movq 4(%ap),%r0 #%r0=x 170 movq 12(%ap),%r2 #%r2=y 171 jeql Rop #if y=0 then generate reserved op fault 172 bicw3 $0x007f,%r0,%r4 #check if x is Rop 173 cmpw %r4,$0x8000 174 jeql Ret #if x is Rop then return Rop 175 bicl3 $0x007f,%r2,%r4 #check if y is Rop 176 cmpw %r4,$0x8000 177 jeql Ret #if y is Rop then return Rop 178 bicw2 $0x8000,%r2 #y := |y| 179 movw $0,-4(%fp) #-4(%fp) = nx := 0 180 cmpw %r2,$0x1c80 #yexp ? 57 181 bgtr C1 #if yexp > 57 goto C1 182 addw2 $0x1c80,%r2 #scale up y by 2**57 183 movw $0x1c80,-4(%fp) #nx := 57 (exponent field) 184 C1: 185 movw -4(%fp),-8(%fp) #-8(%fp) = nf := nx 186 bicw3 $0x7fff,%r0,-12(%fp) #-12(%fp) = sign of x 187 bicw2 $0x8000,%r0 #x := |x| 188 movq %r2,%r10 #y1 := y 189 bicl2 $0xffff07ff,%r11 #clear the last 27 bits of y1 190 loop: 191 cmpd %r0,%r2 #x ? y 192 bleq E1 #if x <= y goto E1 193 /* begin argument reduction */ 194 movq %r2,%r4 #t =y 195 movq %r10,%r6 #t1=y1 196 bicw3 $0x807f,%r0,%r8 #xexp= exponent of x 197 bicw3 $0x807f,%r2,%r9 #yexp= exponent fo y 198 subw2 %r9,%r8 #xexp-yexp 199 subw2 $0x0c80,%r8 #k=xexp-yexp-25(exponent bit field) 200 blss C2 #if k<0 goto C2 201 addw2 %r8,%r4 #t +=k 202 addw2 %r8,%r6 #t1+=k, scale up t and t1 203 C2: 204 divd3 %r4,%r0,%r8 #x/t 205 cvtdl %r8,%r8 #n=[x/t] truncated 206 cvtld %r8,%r8 #float(n) 207 subd2 %r6,%r4 #t:=t-t1 208 muld2 %r8,%r4 #n*(t-t1) 209 muld2 %r8,%r6 #n*t1 210 subd2 %r6,%r0 #x-n*t1 211 subd2 %r4,%r0 #(x-n*t1)-n*(t-t1) 212 jbr loop 213 E1: 214 movw -4(%fp),%r6 #%r6=nx 215 beql C3 #if nx=0 goto C3 216 addw2 %r6,%r0 #x:=x*2**57 scale up x by nx 217 movw $0,-4(%fp) #clear nx 218 jbr loop 219 C3: 220 movq %r2,%r4 #%r4 = y 221 subw2 $0x80,%r4 #%r4 = y/2 222 cmpd %r0,%r4 #x:y/2 223 blss E2 #if x < y/2 goto E2 224 bgtr C4 #if x > y/2 goto C4 225 cvtdl %r8,%r8 #ifix(float(n)) 226 blbc %r8,E2 #if the last bit is zero, goto E2 227 C4: 228 subd2 %r2,%r0 #x-y 229 E2: 230 xorw2 -12(%fp),%r0 #x^sign (exclusive or) 231 movw -8(%fp),%r6 #%r6=nf 232 bicw3 $0x807f,%r0,%r8 #%r8=exponent of x 233 bicw2 $0x7f80,%r0 #clear the exponent of x 234 subw2 %r6,%r8 #%r8=xexp-nf 235 bgtr C5 #if xexp-nf is positive goto C5 236 movw $0,%r8 #clear %r8 237 movq $0,%r0 #x underflow to zero 238 C5: 239 bisw2 %r8,%r0 /* put %r8 into x's exponent field */ 240 ret 241 Rop: #Reserved operand 242 pushl $EDOM 243 calls $1,_C_LABEL(infnan) #generate reserved op fault 244 ret 245 Ret: 246 movq $0x8000,%r0 #propagate reserved op 247 ret 248
Indexes created Tue Sep 30 20:09:53 GMT 2025