n_support.S revision 1.8
1 /* $NetBSD: n_support.S,v 1.8 2014/03/15 12:20:09 martin 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, copysign) 36 37 .text 38 _sccsid: 39 .asciz "@(#)support.s\t1.3 (Berkeley) 8/21/85; 8.1 (ucb.elefunt) 6/4/93" 40 41 /* 42 * copysign(x,y), 43 * logb(x), 44 * scalb(x,N), 45 * finite(x), 46 * drem(x,y), 47 * Coded in vax assembly language by K.C. Ng, 3/14/85. 48 * Revised by K.C. Ng on 4/9/85. 49 */ 50 51 /* 52 * double copysign(double x,double y) 53 */ 54 55 ENTRY(copysign, 0) 56 movq 4(%ap),%r0 # load x into %r0 57 bicw3 $0x807f,%r0,%r2 # mask off the exponent of x 58 beql Lz # if zero or reserved op then return x 59 bicw3 $0x7fff,12(%ap),%r2 # copy the sign bit of y into %r2 60 bicw2 $0x8000,%r0 # replace x by |x| 61 bisw2 %r2,%r0 # copy the sign bit of y to x 62 Lz: ret 63 64 ENTRY(copysignf, 0) 65 movw 4(%ap),%r0 # load x into %r0 66 bicw3 $0x807f,%r0,%r2 # mask off the exponent of x 67 beql 1f # if zero or reserved op then return x 68 bicw3 $0x7fff,8(%ap),%r2 # copy the sign bit of y into %r2 69 bicw2 $0x8000,%r0 # replace x by |x| 70 bisw2 %r2,%r0 # copy the sign bit of y to x 71 1: ret 72 73 /* 74 * float logbf(float x); 75 */ 76 ENTRY(logbf, 0) 77 cvtfd 4(%ap),-(%sp) 78 calls $2,_C_LABEL(logb) 79 cvtdf %r0,%r0 80 ret 81 82 /* 83 * double logb(double x); 84 */ 85 ENTRY(logb, 0) 86 bicl3 $0xffff807f,4(%ap),%r0 # mask off the exponent of x 87 beql Ln 88 ashl $-7,%r0,%r0 # get the bias exponent 89 subl2 $129,%r0 # get the unbias exponent 90 cvtld %r0,%r0 # return the answer in double 91 ret 92 Ln: movq 4(%ap),%r0 # %r0:1 = x (zero or reserved op) 93 bneq 1f # simply return if reserved op 94 movq $0x0000fe00ffffcfff,%r0 # -2147483647.0 95 1: ret 96 97 /* 98 * long finite(double x); 99 */ 100 #ifndef __GFLOAT__ 101 .globl finitef 102 finitef = finite 103 #endif 104 ENTRY(finite, 0) 105 bicw3 $0x7f,4(%ap),%r0 # mask off the mantissa 106 cmpw %r0,$0x8000 # to see if x is the reserved op 107 beql 1f # if so, return FALSE (0) 108 movl $1,%r0 # else return TRUE (1) 109 ret 110 1: clrl %r0 111 ret 112 113 /* int isnan(double x); 114 */ 115 #if 0 116 ENTRY(isnan, 0) 117 clrl %r0 118 ret 119 #endif 120 121 /* int isnanf(float x); 122 */ 123 ENTRY(isnanf, 0) 124 clrl %r0 125 ret 126 127 /* 128 * double scalb(x,N) 129 * double x; double N; 130 */ 131 .set ERANGE,34 132 133 ENTRY(scalb, 0) 134 movq 4(%ap),%r0 135 bicl3 $0xffff807f,%r0,%r3 136 beql ret1 # 0 or reserved operand 137 movq 12(%ap),%r4 138 cvtdl %r4, %r2 139 cmpl %r2,$0x12c 140 bgeq ovfl 141 cmpl %r2,$-0x12c 142 bleq unfl 143 ashl $7,%r2,%r2 144 addl2 %r2,%r3 145 bleq unfl 146 cmpl %r3,$0x8000 147 bgeq ovfl 148 addl2 %r2,%r0 149 ret 150 ovfl: pushl $ERANGE 151 calls $1,_C_LABEL(infnan) # if it returns 152 bicw3 $0x7fff,4(%ap),%r2 # get the sign of input arg 153 bisw2 %r2,%r0 # re-attach the sign to %r0/1 154 ret 155 unfl: movq $0,%r0 156 ret1: ret 157 158 /* 159 * DREM(X,Y) 160 * RETURN X REM Y =X-N*Y, N=[X/Y] ROUNDED (ROUNDED TO EVEN IN THE HALF WAY CASE) 161 * DOUBLE PRECISION (VAX D format 56 bits) 162 * CODED IN VAX ASSEMBLY LANGUAGE BY K.C. NG, 4/8/85. 163 */ 164 .set EDOM,33 165 166 ENTRY(drem, 0x0fc0) 167 subl2 $12,%sp 168 movq 4(%ap),%r0 #%r0=x 169 movq 12(%ap),%r2 #%r2=y 170 jeql Rop #if y=0 then generate reserved op fault 171 bicw3 $0x007f,%r0,%r4 #check if x is Rop 172 cmpw %r4,$0x8000 173 jeql Ret #if x is Rop then return Rop 174 bicl3 $0x007f,%r2,%r4 #check if y is Rop 175 cmpw %r4,$0x8000 176 jeql Ret #if y is Rop then return Rop 177 bicw2 $0x8000,%r2 #y := |y| 178 movw $0,-4(%fp) #-4(%fp) = nx := 0 179 cmpw %r2,$0x1c80 #yexp ? 57 180 bgtr C1 #if yexp > 57 goto C1 181 addw2 $0x1c80,%r2 #scale up y by 2**57 182 movw $0x1c80,-4(%fp) #nx := 57 (exponent field) 183 C1: 184 movw -4(%fp),-8(%fp) #-8(%fp) = nf := nx 185 bicw3 $0x7fff,%r0,-12(%fp) #-12(%fp) = sign of x 186 bicw2 $0x8000,%r0 #x := |x| 187 movq %r2,%r10 #y1 := y 188 bicl2 $0xffff07ff,%r11 #clear the last 27 bits of y1 189 loop: 190 cmpd %r0,%r2 #x ? y 191 bleq E1 #if x <= y goto E1 192 /* begin argument reduction */ 193 movq %r2,%r4 #t =y 194 movq %r10,%r6 #t1=y1 195 bicw3 $0x807f,%r0,%r8 #xexp= exponent of x 196 bicw3 $0x807f,%r2,%r9 #yexp= exponent fo y 197 subw2 %r9,%r8 #xexp-yexp 198 subw2 $0x0c80,%r8 #k=xexp-yexp-25(exponent bit field) 199 blss C2 #if k<0 goto C2 200 addw2 %r8,%r4 #t +=k 201 addw2 %r8,%r6 #t1+=k, scale up t and t1 202 C2: 203 divd3 %r4,%r0,%r8 #x/t 204 cvtdl %r8,%r8 #n=[x/t] truncated 205 cvtld %r8,%r8 #float(n) 206 subd2 %r6,%r4 #t:=t-t1 207 muld2 %r8,%r4 #n*(t-t1) 208 muld2 %r8,%r6 #n*t1 209 subd2 %r6,%r0 #x-n*t1 210 subd2 %r4,%r0 #(x-n*t1)-n*(t-t1) 211 jbr loop 212 E1: 213 movw -4(%fp),%r6 #%r6=nx 214 beql C3 #if nx=0 goto C3 215 addw2 %r6,%r0 #x:=x*2**57 scale up x by nx 216 movw $0,-4(%fp) #clear nx 217 jbr loop 218 C3: 219 movq %r2,%r4 #%r4 = y 220 subw2 $0x80,%r4 #%r4 = y/2 221 cmpd %r0,%r4 #x:y/2 222 blss E2 #if x < y/2 goto E2 223 bgtr C4 #if x > y/2 goto C4 224 cvtdl %r8,%r8 #ifix(float(n)) 225 blbc %r8,E2 #if the last bit is zero, goto E2 226 C4: 227 subd2 %r2,%r0 #x-y 228 E2: 229 xorw2 -12(%fp),%r0 #x^sign (exclusive or) 230 movw -8(%fp),%r6 #%r6=nf 231 bicw3 $0x807f,%r0,%r8 #%r8=exponent of x 232 bicw2 $0x7f80,%r0 #clear the exponent of x 233 subw2 %r6,%r8 #%r8=xexp-nf 234 bgtr C5 #if xexp-nf is positive goto C5 235 movw $0,%r8 #clear %r8 236 movq $0,%r0 #x underflow to zero 237 C5: 238 bisw2 %r8,%r0 /* put %r8 into x's exponent field */ 239 ret 240 Rop: #Reserved operand 241 pushl $EDOM 242 calls $1,_C_LABEL(infnan) #generate reserved op fault 243 ret 244 Ret: 245 movq $0x8000,%r0 #propagate reserved op 246 ret 247
Indexes created Tue Sep 30 20:09:53 GMT 2025