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to fp value to be stored. 9 | 10 11 | Copyright (C) Motorola, Inc. 1990 12 | All Rights Reserved 13 | 14 | THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 15 | The copyright notice above does not evidence any 16 | actual or intended publication of such source code. 17 18 X_STORE: |idnt 2,1 | Motorola 040 Floating Point Software Package 19 20 |section 8 21 22 fpreg_mask: 23 .byte 0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01 24 25 .include "fpsp.h" 26 27 |xref mem_write 28 |xref get_fline 29 |xref g_opcls 30 |xref g_dfmtou 31 |xref reg_dest 32 33 .global dest_ext 34 .global dest_dbl 35 .global dest_sgl 36 37 .global store 38 store: 39 btstb #E3,E_BYTE(%a6) 40 beqs E1_sto 41 E3_sto: 42 movel CMDREG3B(%a6),%d0 43 bfextu %d0{#6:#3},%d0 |isolate dest. reg from cmdreg3b 44 sto_fp: 45 lea fpreg_mask,%a1 46 moveb (%a1,%d0.w),%d0 |convert reg# to dynamic register mask 47 tstb LOCAL_SGN(%a0) 48 beqs is_pos 49 bsetb #sign_bit,LOCAL_EX(%a0) 50 is_pos: 51 fmovemx (%a0),%d0 |move to correct register 52 | 53 | if fp0-fp3 is being modified, we must put a copy 54 | in the USER_FPn variable on the stack because all exception 55 | handlers restore fp0-fp3 from there. 56 | 57 cmpb #0x80,%d0 58 bnes not_fp0 59 fmovemx %fp0-%fp0,USER_FP0(%a6) 60 rts 61 not_fp0: 62 cmpb #0x40,%d0 63 bnes not_fp1 64 fmovemx %fp1-%fp1,USER_FP1(%a6) 65 rts 66 not_fp1: 67 cmpb #0x20,%d0 68 bnes not_fp2 69 fmovemx %fp2-%fp2,USER_FP2(%a6) 70 rts 71 not_fp2: 72 cmpb #0x10,%d0 73 bnes not_fp3 74 fmovemx %fp3-%fp3,USER_FP3(%a6) 75 rts 76 not_fp3: 77 rts 78 79 E1_sto: 80 bsrl g_opcls |returns opclass in d0 81 cmpib #3,%d0 82 beq opc011 |branch if opclass 3 83 movel CMDREG1B(%a6),%d0 84 bfextu %d0{#6:#3},%d0 |extract destination register 85 bras sto_fp 86 87 opc011: 88 bsrl g_dfmtou |returns dest format in d0 89 | ;ext=00, sgl=01, dbl=10 90 movel %a0,%a1 |save source addr in a1 91 movel EXC_EA(%a6),%a0 |get the address 92 cmpil #0,%d0 |if dest format is extended 93 beq dest_ext |then branch 94 cmpil #1,%d0 |if dest format is single 95 beqs dest_sgl |then branch 96 | 97 | fall through to dest_dbl 98 | 99 100 | 101 | dest_dbl --- write double precision value to user space 102 | 103 |Input 104 | a0 -> destination address 105 | a1 -> source in extended precision 106 |Output 107 | a0 -> destroyed 108 | a1 -> destroyed 109 | d0 -> 0 110 | 111 |Changes extended precision to double precision. 112 | Note: no attempt is made to round the extended value to double. 113 | dbl_sign = ext_sign 114 | dbl_exp = ext_exp - $3fff(ext bias) + $7ff(dbl bias) 115 | get rid of ext integer bit 116 | dbl_mant = ext_mant{62:12} 117 | 118 | --------------- --------------- --------------- 119 | extended -> |s| exp | |1| ms mant | | ls mant | 120 | --------------- --------------- --------------- 121 | 95 64 63 62 32 31 11 0 122 | | | 123 | | | 124 | | | 125 | v v 126 | --------------- --------------- 127 | double -> |s|exp| mant | | mant | 128 | --------------- --------------- 129 | 63 51 32 31 0 130 | 131 dest_dbl: 132 clrl %d0 |clear d0 133 movew LOCAL_EX(%a1),%d0 |get exponent 134 subw #0x3fff,%d0 |subtract extended precision bias 135 cmpw #0x4000,%d0 |check if inf 136 beqs inf |if so, special case 137 addw #0x3ff,%d0 |add double precision bias 138 swap %d0 |d0 now in upper word 139 lsll #4,%d0 |d0 now in proper place for dbl prec exp 140 tstb LOCAL_SGN(%a1) 141 beqs get_mant |if positive, go process mantissa 142 bsetl #31,%d0 |if negative, put in sign information 143 | ; before continuing 144 bras get_mant |go process mantissa 145 inf: 146 movel #0x7ff00000,%d0 |load dbl inf exponent 147 clrl LOCAL_HI(%a1) |clear msb 148 tstb LOCAL_SGN(%a1) 149 beqs dbl_inf |if positive, go ahead and write it 150 bsetl #31,%d0 |if negative put in sign information 151 dbl_inf: 152 movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack 153 bras dbl_wrt 154 get_mant: 155 movel LOCAL_HI(%a1),%d1 |get ms mantissa 156 bfextu %d1{#1:#20},%d1 |get upper 20 bits of ms 157 orl %d1,%d0 |put these bits in ms word of double 158 movel %d0,LOCAL_EX(%a1) |put the new exp back on the stack 159 movel LOCAL_HI(%a1),%d1 |get ms mantissa 160 movel #21,%d0 |load shift count 161 lsll %d0,%d1 |put lower 11 bits in upper bits 162 movel %d1,LOCAL_HI(%a1) |build lower lword in memory 163 movel LOCAL_LO(%a1),%d1 |get ls mantissa 164 bfextu %d1{#0:#21},%d0 |get ls 21 bits of double 165 orl %d0,LOCAL_HI(%a1) |put them in double result 166 dbl_wrt: 167 movel #0x8,%d0 |byte count for double precision number 168 exg %a0,%a1 |a0=supervisor source, a1=user dest 169 bsrl mem_write |move the number to the user's memory 170 rts 171 | 172 | dest_sgl --- write single precision value to user space 173 | 174 |Input 175 | a0 -> destination address 176 | a1 -> source in extended precision 177 | 178 |Output 179 | a0 -> destroyed 180 | a1 -> destroyed 181 | d0 -> 0 182 | 183 |Changes extended precision to single precision. 184 | sgl_sign = ext_sign 185 | sgl_exp = ext_exp - $3fff(ext bias) + $7f(sgl bias) 186 | get rid of ext integer bit 187 | sgl_mant = ext_mant{62:12} 188 | 189 | --------------- --------------- --------------- 190 | extended -> |s| exp | |1| ms mant | | ls mant | 191 | --------------- --------------- --------------- 192 | 95 64 63 62 40 32 31 12 0 193 | | | 194 | | | 195 | | | 196 | v v 197 | --------------- 198 | single -> |s|exp| mant | 199 | --------------- 200 | 31 22 0 201 | 202 dest_sgl: 203 clrl %d0 204 movew LOCAL_EX(%a1),%d0 |get exponent 205 subw #0x3fff,%d0 |subtract extended precision bias 206 cmpw #0x4000,%d0 |check if inf 207 beqs sinf |if so, special case 208 addw #0x7f,%d0 |add single precision bias 209 swap %d0 |put exp in upper word of d0 210 lsll #7,%d0 |shift it into single exp bits 211 tstb LOCAL_SGN(%a1) 212 beqs get_sman |if positive, continue 213 bsetl #31,%d0 |if negative, put in sign first 214 bras get_sman |get mantissa 215 sinf: 216 movel #0x7f800000,%d0 |load single inf exp to d0 217 tstb LOCAL_SGN(%a1) 218 beqs sgl_wrt |if positive, continue 219 bsetl #31,%d0 |if negative, put in sign info 220 bras sgl_wrt 221 222 get_sman: 223 movel LOCAL_HI(%a1),%d1 |get ms mantissa 224 bfextu %d1{#1:#23},%d1 |get upper 23 bits of ms 225 orl %d1,%d0 |put these bits in ms word of single 226 227 sgl_wrt: 228 movel %d0,L_SCR1(%a6) |put the new exp back on the stack 229 movel #0x4,%d0 |byte count for single precision number 230 tstl %a0 |users destination address 231 beqs sgl_Dn |destination is a data register 232 exg %a0,%a1 |a0=supervisor source, a1=user dest 233 leal L_SCR1(%a6),%a0 |point a0 to data 234 bsrl mem_write |move the number to the user's memory 235 rts 236 sgl_Dn: 237 bsrl get_fline |returns fline word in d0 238 andw #0x7,%d0 |isolate register number 239 movel %d0,%d1 |d1 has size:reg formatted for reg_dest 240 orl #0x10,%d1 |reg_dest wants size added to reg# 241 bral reg_dest |size is X, rts in reg_dest will 242 | ;return to caller of dest_sgl 243 244 dest_ext: 245 tstb LOCAL_SGN(%a1) |put back sign into exponent word 246 beqs dstx_cont 247 bsetb #sign_bit,LOCAL_EX(%a1) 248 dstx_cont: 249 clrb LOCAL_SGN(%a1) |clear out the sign byte 250 251 movel #0x0c,%d0 |byte count for extended number 252 exg %a0,%a1 |a0=supervisor source, a1=user dest 253 bsrl mem_write |move the number to the user's memory 254 rts 255 256 |end