x_store.S (6983B)
1| 2| x_store.sa 3.2 1/24/91 3| 4| store --- store operand to memory or register 5| 6| Used by underflow and overflow handlers. 7| 8| a6 = points to fp value to be stored. 9| 10 11| Copyright (C) Motorola, Inc. 1990 12| All Rights Reserved 13| 14| For details on the license for this file, please see the 15| file, README, in this same directory. 16 17X_STORE: |idnt 2,1 | Motorola 040 Floating Point Software Package 18 19 |section 8 20 21fpreg_mask: 22 .byte 0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01 23 24#include "fpsp.h" 25 26 |xref mem_write 27 |xref get_fline 28 |xref g_opcls 29 |xref g_dfmtou 30 |xref reg_dest 31 32 .global dest_ext 33 .global dest_dbl 34 .global dest_sgl 35 36 .global store 37store: 38 btstb #E3,E_BYTE(%a6) 39 beqs E1_sto 40E3_sto: 41 movel CMDREG3B(%a6),%d0 42 bfextu %d0{#6:#3},%d0 |isolate dest. reg from cmdreg3b 43sto_fp: 44 lea fpreg_mask,%a1 45 moveb (%a1,%d0.w),%d0 |convert reg# to dynamic register mask 46 tstb LOCAL_SGN(%a0) 47 beqs is_pos 48 bsetb #sign_bit,LOCAL_EX(%a0) 49is_pos: 50 fmovemx (%a0),%d0 |move to correct register 51| 52| if fp0-fp3 is being modified, we must put a copy 53| in the USER_FPn variable on the stack because all exception 54| handlers restore fp0-fp3 from there. 55| 56 cmpb #0x80,%d0 57 bnes not_fp0 58 fmovemx %fp0-%fp0,USER_FP0(%a6) 59 rts 60not_fp0: 61 cmpb #0x40,%d0 62 bnes not_fp1 63 fmovemx %fp1-%fp1,USER_FP1(%a6) 64 rts 65not_fp1: 66 cmpb #0x20,%d0 67 bnes not_fp2 68 fmovemx %fp2-%fp2,USER_FP2(%a6) 69 rts 70not_fp2: 71 cmpb #0x10,%d0 72 bnes not_fp3 73 fmovemx %fp3-%fp3,USER_FP3(%a6) 74 rts 75not_fp3: 76 rts 77 78E1_sto: 79 bsrl g_opcls |returns opclass in d0 80 cmpib #3,%d0 81 beq opc011 |branch if opclass 3 82 movel CMDREG1B(%a6),%d0 83 bfextu %d0{#6:#3},%d0 |extract destination register 84 bras sto_fp 85 86opc011: 87 bsrl g_dfmtou |returns dest format in d0 88| ;ext=00, sgl=01, dbl=10 89 movel %a0,%a1 |save source addr in a1 90 movel EXC_EA(%a6),%a0 |get the address 91 cmpil #0,%d0 |if dest format is extended 92 beq dest_ext |then branch 93 cmpil #1,%d0 |if dest format is single 94 beq dest_sgl |then branch 95| 96| fall through to dest_dbl 97| 98 99| 100| dest_dbl --- write double precision value to user space 101| 102|Input 103| a0 -> destination address 104| a1 -> source in extended precision 105|Output 106| a0 -> destroyed 107| a1 -> destroyed 108| d0 -> 0 109| 110|Changes extended precision to double precision. 111| Note: no attempt is made to round the extended value to double. 112| dbl_sign = ext_sign 113| dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias) 114| get rid of ext integer bit 115| dbl_mant = ext_mant{62:12} 116| 117| --------------- --------------- --------------- 118| extended -> |s| exp | |1| ms mant | | ls mant | 119| --------------- --------------- --------------- 120| 95 64 63 62 32 31 11 0 121| | | 122| | | 123| | | 124| v v 125| --------------- --------------- 126| double -> |s|exp| mant | | mant | 127| --------------- --------------- 128| 63 51 32 31 0 129| 130dest_dbl: 131 clrl %d0 |clear d0 132 movew LOCAL_EX(%a1),%d0 |get exponent 133 subw #0x3fff,%d0 |subtract extended precision bias 134 cmpw #0x4000,%d0 |check if inf 135 beqs inf |if so, special case 136 addw #0x3ff,%d0 |add double precision bias 137 swap %d0 |d0 now in upper word 138 lsll #4,%d0 |d0 now in proper place for dbl prec exp 139 tstb LOCAL_SGN(%a1) 140 beqs get_mant |if positive, go process mantissa 141 bsetl #31,%d0 |if negative, put in sign information 142| ; before continuing 143 bras get_mant |go process mantissa 144inf: 145 movel #0x7ff00000,%d0 |load dbl inf exponent 146 clrl LOCAL_HI(%a1) |clear msb 147 tstb LOCAL_SGN(%a1) 148 beqs dbl_inf |if positive, go ahead and write it 149 bsetl #31,%d0 |if negative put in sign information 150dbl_inf: 151 movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack 152 bras dbl_wrt 153get_mant: 154 movel LOCAL_HI(%a1),%d1 |get ms mantissa 155 bfextu %d1{#1:#20},%d1 |get upper 20 bits of ms 156 orl %d1,%d0 |put these bits in ms word of double 157 movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack 158 movel LOCAL_HI(%a1),%d1 |get ms mantissa 159 movel #21,%d0 |load shift count 160 lsll %d0,%d1 |put lower 11 bits in upper bits 161 movel %d1,LOCAL_HI(%a1) |build lower lword in memory 162 movel LOCAL_LO(%a1),%d1 |get ls mantissa 163 bfextu %d1{#0:#21},%d0 |get ls 21 bits of double 164 orl %d0,LOCAL_HI(%a1) |put them in double result 165dbl_wrt: 166 movel #0x8,%d0 |byte count for double precision number 167 exg %a0,%a1 |a0=supervisor source, a1=user dest 168 bsrl mem_write |move the number to the user's memory 169 rts 170| 171| dest_sgl --- write single precision value to user space 172| 173|Input 174| a0 -> destination address 175| a1 -> source in extended precision 176| 177|Output 178| a0 -> destroyed 179| a1 -> destroyed 180| d0 -> 0 181| 182|Changes extended precision to single precision. 183| sgl_sign = ext_sign 184| sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias) 185| get rid of ext integer bit 186| sgl_mant = ext_mant{62:12} 187| 188| --------------- --------------- --------------- 189| extended -> |s| exp | |1| ms mant | | ls mant | 190| --------------- --------------- --------------- 191| 95 64 63 62 40 32 31 12 0 192| | | 193| | | 194| | | 195| v v 196| --------------- 197| single -> |s|exp| mant | 198| --------------- 199| 31 22 0 200| 201dest_sgl: 202 clrl %d0 203 movew LOCAL_EX(%a1),%d0 |get exponent 204 subw #0x3fff,%d0 |subtract extended precision bias 205 cmpw #0x4000,%d0 |check if inf 206 beqs sinf |if so, special case 207 addw #0x7f,%d0 |add single precision bias 208 swap %d0 |put exp in upper word of d0 209 lsll #7,%d0 |shift it into single exp bits 210 tstb LOCAL_SGN(%a1) 211 beqs get_sman |if positive, continue 212 bsetl #31,%d0 |if negative, put in sign first 213 bras get_sman |get mantissa 214sinf: 215 movel #0x7f800000,%d0 |load single inf exp to d0 216 tstb LOCAL_SGN(%a1) 217 beqs sgl_wrt |if positive, continue 218 bsetl #31,%d0 |if negative, put in sign info 219 bras sgl_wrt 220 221get_sman: 222 movel LOCAL_HI(%a1),%d1 |get ms mantissa 223 bfextu %d1{#1:#23},%d1 |get upper 23 bits of ms 224 orl %d1,%d0 |put these bits in ms word of single 225 226sgl_wrt: 227 movel %d0,L_SCR1(%a6) |put the new exp back on the stack 228 movel #0x4,%d0 |byte count for single precision number 229 tstl %a0 |users destination address 230 beqs sgl_Dn |destination is a data register 231 exg %a0,%a1 |a0=supervisor source, a1=user dest 232 leal L_SCR1(%a6),%a0 |point a0 to data 233 bsrl mem_write |move the number to the user's memory 234 rts 235sgl_Dn: 236 bsrl get_fline |returns fline word in d0 237 andw #0x7,%d0 |isolate register number 238 movel %d0,%d1 |d1 has size:reg formatted for reg_dest 239 orl #0x10,%d1 |reg_dest wants size added to reg# 240 bral reg_dest |size is X, rts in reg_dest will 241| ;return to caller of dest_sgl 242 243dest_ext: 244 tstb LOCAL_SGN(%a1) |put back sign into exponent word 245 beqs dstx_cont 246 bsetb #sign_bit,LOCAL_EX(%a1) 247dstx_cont: 248 clrb LOCAL_SGN(%a1) |clear out the sign byte 249 250 movel #0x0c,%d0 |byte count for extended number 251 exg %a0,%a1 |a0=supervisor source, a1=user dest 252 bsrl mem_write |move the number to the user's memory 253 rts 254 255 |end