1* $NetBSD: sint.sa,v 1.2 1994/10/26 07:49:48 cgd Exp $ 2 3* MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP 4* M68000 Hi-Performance Microprocessor Division 5* M68040 Software Package 6* 7* M68040 Software Package Copyright (c) 1993, 1994 Motorola Inc. 8* All rights reserved. 9* 10* THE SOFTWARE is provided on an "AS IS" basis and without warranty. 11* To the maximum extent permitted by applicable law, 12* MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED, 13* INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A 14* PARTICULAR PURPOSE and any warranty against infringement with 15* regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF) 16* and any accompanying written materials. 17* 18* To the maximum extent permitted by applicable law, 19* IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER 20* (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS 21* PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR 22* OTHER PECUNIARY LOSS) ARISING OF THE USE OR INABILITY TO USE THE 23* SOFTWARE. Motorola assumes no responsibility for the maintenance 24* and support of the SOFTWARE. 25* 26* You are hereby granted a copyright license to use, modify, and 27* distribute the SOFTWARE so long as this entire notice is retained 28* without alteration in any modified and/or redistributed versions, 29* and that such modified versions are clearly identified as such. 30* No licenses are granted by implication, estoppel or otherwise 31* under any patents or trademarks of Motorola, Inc. 32 33* 34* sint.sa 3.1 12/10/90 35* 36* The entry point sINT computes the rounded integer 37* equivalent of the input argument, sINTRZ computes 38* the integer rounded to zero of the input argument. 39* 40* Entry points sint and sintrz are called from do_func 41* to emulate the fint and fintrz unimplemented instructions, 42* respectively. Entry point sintdo is used by bindec. 43* 44* Input: (Entry points sint and sintrz) Double-extended 45* number X in the ETEMP space in the floating-point 46* save stack. 47* (Entry point sintdo) Double-extended number X in 48* location pointed to by the address register a0. 49* (Entry point sintd) Double-extended denormalized 50* number X in the ETEMP space in the floating-point 51* save stack. 52* 53* Output: The function returns int(X) or intrz(X) in fp0. 54* 55* Modifies: fp0. 56* 57* Algorithm: (sint and sintrz) 58* 59* 1. If exp(X) >= 63, return X. 60* If exp(X) < 0, return +/- 0 or +/- 1, according to 61* the rounding mode. 62* 63* 2. (X is in range) set rsc = 63 - exp(X). Unnormalize the 64* result to the exponent $403e. 65* 66* 3. Round the result in the mode given in USER_FPCR. For 67* sintrz, force round-to-zero mode. 68* 69* 4. Normalize the rounded result; store in fp0. 70* 71* For the denormalized cases, force the correct result 72* for the given sign and rounding mode. 73* 74* Sign(X) 75* RMODE + - 76* ----- -------- 77* RN +0 -0 78* RZ +0 -0 79* RM +0 -1 80* RP +1 -0 81* 82 83SINT IDNT 2,1 Motorola 040 Floating Point Software Package 84 85 section 8 86 87 include fpsp.h 88 89 xref dnrm_lp 90 xref nrm_set 91 xref round 92 xref t_inx2 93 xref ld_pone 94 xref ld_mone 95 xref ld_pzero 96 xref ld_mzero 97 xref snzrinx 98 99* 100* FINT 101* 102 xdef sint 103sint: 104 bfextu FPCR_MODE(a6){2:2},d1 ;use user's mode for rounding 105* ;implicity has extend precision 106* ;in upper word. 107 move.l d1,L_SCR1(a6) ;save mode bits 108 bra.b sintexc 109 110* 111* FINT with extended denorm inputs. 112* 113 xdef sintd 114sintd: 115 btst.b #5,FPCR_MODE(a6) 116 beq snzrinx ;if round nearest or round zero, +/- 0 117 btst.b #4,FPCR_MODE(a6) 118 beq.b rnd_mns 119rnd_pls: 120 btst.b #sign_bit,LOCAL_EX(a0) 121 bne.b sintmz 122 bsr ld_pone ;if round plus inf and pos, answer is +1 123 bra t_inx2 124rnd_mns: 125 btst.b #sign_bit,LOCAL_EX(a0) 126 beq.b sintpz 127 bsr ld_mone ;if round mns inf and neg, answer is -1 128 bra t_inx2 129sintpz: 130 bsr ld_pzero 131 bra t_inx2 132sintmz: 133 bsr ld_mzero 134 bra t_inx2 135 136* 137* FINTRZ 138* 139 xdef sintrz 140sintrz: 141 move.l #1,L_SCR1(a6) ;use rz mode for rounding 142* ;implicity has extend precision 143* ;in upper word. 144 bra.b sintexc 145* 146* SINTDO 147* 148* Input: a0 points to an IEEE extended format operand 149* Output: fp0 has the result 150* 151* Exeptions: 152* 153* If the subroutine results in an inexact operation, the inx2 and 154* ainx bits in the USER_FPSR are set. 155* 156* 157 xdef sintdo 158sintdo: 159 bfextu FPCR_MODE(a6){2:2},d1 ;use user's mode for rounding 160* ;implicitly has ext precision 161* ;in upper word. 162 move.l d1,L_SCR1(a6) ;save mode bits 163* 164* Real work of sint is in sintexc 165* 166sintexc: 167 bclr.b #sign_bit,LOCAL_EX(a0) ;convert to internal extended 168* ;format 169 sne LOCAL_SGN(a0) 170 cmp.w #$403e,LOCAL_EX(a0) ;check if (unbiased) exp > 63 171 bgt.b out_rnge ;branch if exp < 63 172 cmp.w #$3ffd,LOCAL_EX(a0) ;check if (unbiased) exp < 0 173 bgt.w in_rnge ;if 63 >= exp > 0, do calc 174* 175* Input is less than zero. Restore sign, and check for directed 176* rounding modes. L_SCR1 contains the rmode in the lower byte. 177* 178un_rnge: 179 btst.b #1,L_SCR1+3(a6) ;check for rn and rz 180 beq.b un_rnrz 181 tst.b LOCAL_SGN(a0) ;check for sign 182 bne.b un_rmrp_neg 183* 184* Sign is +. If rp, load +1.0, if rm, load +0.0 185* 186 cmpi.b #3,L_SCR1+3(a6) ;check for rp 187 beq.b un_ldpone ;if rp, load +1.0 188 bsr ld_pzero ;if rm, load +0.0 189 bra t_inx2 190un_ldpone: 191 bsr ld_pone 192 bra t_inx2 193* 194* Sign is -. If rm, load -1.0, if rp, load -0.0 195* 196un_rmrp_neg: 197 cmpi.b #2,L_SCR1+3(a6) ;check for rm 198 beq.b un_ldmone ;if rm, load -1.0 199 bsr ld_mzero ;if rp, load -0.0 200 bra t_inx2 201un_ldmone: 202 bsr ld_mone 203 bra t_inx2 204* 205* Rmode is rn or rz; return signed zero 206* 207un_rnrz: 208 tst.b LOCAL_SGN(a0) ;check for sign 209 bne.b un_rnrz_neg 210 bsr ld_pzero 211 bra t_inx2 212un_rnrz_neg: 213 bsr ld_mzero 214 bra t_inx2 215 216* 217* Input is greater than 2^63. All bits are significant. Return 218* the input. 219* 220out_rnge: 221 bfclr LOCAL_SGN(a0){0:8} ;change back to IEEE ext format 222 beq.b intps 223 bset.b #sign_bit,LOCAL_EX(a0) 224intps: 225 fmove.l fpcr,-(sp) 226 fmove.l #0,fpcr 227 fmove.x LOCAL_EX(a0),fp0 ;if exp > 63 228* ;then return X to the user 229* ;there are no fraction bits 230 fmove.l (sp)+,fpcr 231 rts 232 233in_rnge: 234* ;shift off fraction bits 235 clr.l d0 ;clear d0 - initial g,r,s for 236* ;dnrm_lp 237 move.l #$403e,d1 ;set threshold for dnrm_lp 238* ;assumes a0 points to operand 239 bsr dnrm_lp 240* ;returns unnormalized number 241* ;pointed by a0 242* ;output d0 supplies g,r,s 243* ;used by round 244 move.l L_SCR1(a6),d1 ;use selected rounding mode 245* 246* 247 bsr round ;round the unnorm based on users 248* ;input a0 ptr to ext X 249* ; d0 g,r,s bits 250* ; d1 PREC/MODE info 251* ;output a0 ptr to rounded result 252* ;inexact flag set in USER_FPSR 253* ;if initial grs set 254* 255* normalize the rounded result and store value in fp0 256* 257 bsr nrm_set ;normalize the unnorm 258* ;Input: a0 points to operand to 259* ;be normalized 260* ;Output: a0 points to normalized 261* ;result 262 bfclr LOCAL_SGN(a0){0:8} 263 beq.b nrmrndp 264 bset.b #sign_bit,LOCAL_EX(a0) ;return to IEEE extended format 265nrmrndp: 266 fmove.l fpcr,-(sp) 267 fmove.l #0,fpcr 268 fmove.x LOCAL_EX(a0),fp0 ;move result to fp0 269 fmove.l (sp)+,fpcr 270 rts 271 272 end 273