1| 2| x_operr.sa 3.5 7/1/91 3| 4| fpsp_operr --- FPSP handler for operand error exception 5| 6| See 68040 User's Manual pp. 9-44f 7| 8| Note 1: For trap disabled 040 does the following: 9| If the dest is a fp reg, then an extended precision non_signaling 10| NAN is stored in the dest reg. If the dest format is b, w, or l and 11| the source op is a NAN, then garbage is stored as the result (actually 12| the upper 32 bits of the mantissa are sent to the integer unit). If 13| the dest format is integer (b, w, l) and the operr is caused by 14| integer overflow, or the source op is inf, then the result stored is 15| garbage. 16| There are three cases in which operr is incorrectly signaled on the 17| 040. This occurs for move_out of format b, w, or l for the largest 18| negative integer (-2^7 for b, -2^15 for w, -2^31 for l). 19| 20| On opclass = 011 fmove.(b,w,l) that causes a conversion 21| overflow -> OPERR, the exponent in wbte (and fpte) is: 22| byte 56 - (62 - exp) 23| word 48 - (62 - exp) 24| long 32 - (62 - exp) 25| 26| where exp = (true exp) - 1 27| 28| So, wbtemp and fptemp will contain the following on erroneously 29| signalled operr: 30| fpts = 1 31| fpte = $4000 (15 bit externally) 32| byte fptm = $ffffffff ffffff80 33| word fptm = $ffffffff ffff8000 34| long fptm = $ffffffff 80000000 35| 36| Note 2: For trap enabled 040 does the following: 37| If the inst is move_out, then same as Note 1. 38| If the inst is not move_out, the dest is not modified. 39| The exceptional operand is not defined for integer overflow 40| during a move_out. 41| 42 43| Copyright (C) Motorola, Inc. 1990 44| All Rights Reserved 45| 46| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 47| The copyright notice above does not evidence any 48| actual or intended publication of such source code. 49 50X_OPERR: |idnt 2,1 | Motorola 040 Floating Point Software Package 51 52 |section 8 53 54 .include "fpsp.h" 55 56 |xref mem_write 57 |xref real_operr 58 |xref real_inex 59 |xref get_fline 60 |xref fpsp_done 61 |xref reg_dest 62 63 .global fpsp_operr 64fpsp_operr: 65| 66 link %a6,#-LOCAL_SIZE 67 fsave -(%a7) 68 moveml %d0-%d1/%a0-%a1,USER_DA(%a6) 69 fmovemx %fp0-%fp3,USER_FP0(%a6) 70 fmoveml %fpcr/%fpsr/%fpiar,USER_FPCR(%a6) 71 72| 73| Check if this is an opclass 3 instruction. 74| If so, fall through, else branch to operr_end 75| 76 btstb #TFLAG,T_BYTE(%a6) 77 beqs operr_end 78 79| 80| If the destination size is B,W,or L, the operr must be 81| handled here. 82| 83 movel CMDREG1B(%a6),%d0 84 bfextu %d0{#3:#3},%d0 |0=long, 4=word, 6=byte 85 cmpib #0,%d0 |determine size; check long 86 beq operr_long 87 cmpib #4,%d0 |check word 88 beq operr_word 89 cmpib #6,%d0 |check byte 90 beq operr_byte 91 92| 93| The size is not B,W,or L, so the operr is handled by the 94| kernel handler. Set the operr bits and clean up, leaving 95| only the integer exception frame on the stack, and the 96| fpu in the original exceptional state. 97| 98operr_end: 99 bsetb #operr_bit,FPSR_EXCEPT(%a6) 100 bsetb #aiop_bit,FPSR_AEXCEPT(%a6) 101 102 moveml USER_DA(%a6),%d0-%d1/%a0-%a1 103 fmovemx USER_FP0(%a6),%fp0-%fp3 104 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar 105 frestore (%a7)+ 106 unlk %a6 107 bral real_operr 108 109operr_long: 110 moveql #4,%d1 |write size to d1 111 moveb STAG(%a6),%d0 |test stag for nan 112 andib #0xe0,%d0 |clr all but tag 113 cmpib #0x60,%d0 |check for nan 114 beq operr_nan 115 cmpil #0x80000000,FPTEMP_LO(%a6) |test if ls lword is special 116 bnes chklerr |if not equal, check for incorrect operr 117 bsr check_upper |check if exp and ms mant are special 118 tstl %d0 119 bnes chklerr |if d0 is true, check for incorrect operr 120 movel #0x80000000,%d0 |store special case result 121 bsr operr_store 122 bra not_enabled |clean and exit 123| 124| CHECK FOR INCORRECTLY GENERATED OPERR EXCEPTION HERE 125| 126chklerr: 127 movew FPTEMP_EX(%a6),%d0 128 andw #0x7FFF,%d0 |ignore sign bit 129 cmpw #0x3FFE,%d0 |this is the only possible exponent value 130 bnes chklerr2 131fixlong: 132 movel FPTEMP_LO(%a6),%d0 133 bsr operr_store 134 bra not_enabled 135chklerr2: 136 movew FPTEMP_EX(%a6),%d0 137 andw #0x7FFF,%d0 |ignore sign bit 138 cmpw #0x4000,%d0 139 bcc store_max |exponent out of range 140 141 movel FPTEMP_LO(%a6),%d0 142 andl #0x7FFF0000,%d0 |look for all 1's on bits 30-16 143 cmpl #0x7FFF0000,%d0 144 beqs fixlong 145 146 tstl FPTEMP_LO(%a6) 147 bpls chklepos 148 cmpl #0xFFFFFFFF,FPTEMP_HI(%a6) 149 beqs fixlong 150 bra store_max 151chklepos: 152 tstl FPTEMP_HI(%a6) 153 beqs fixlong 154 bra store_max 155 156operr_word: 157 moveql #2,%d1 |write size to d1 158 moveb STAG(%a6),%d0 |test stag for nan 159 andib #0xe0,%d0 |clr all but tag 160 cmpib #0x60,%d0 |check for nan 161 beq operr_nan 162 cmpil #0xffff8000,FPTEMP_LO(%a6) |test if ls lword is special 163 bnes chkwerr |if not equal, check for incorrect operr 164 bsr check_upper |check if exp and ms mant are special 165 tstl %d0 166 bnes chkwerr |if d0 is true, check for incorrect operr 167 movel #0x80000000,%d0 |store special case result 168 bsr operr_store 169 bra not_enabled |clean and exit 170| 171| CHECK FOR INCORRECTLY GENERATED OPERR EXCEPTION HERE 172| 173chkwerr: 174 movew FPTEMP_EX(%a6),%d0 175 andw #0x7FFF,%d0 |ignore sign bit 176 cmpw #0x3FFE,%d0 |this is the only possible exponent value 177 bnes store_max 178 movel FPTEMP_LO(%a6),%d0 179 swap %d0 180 bsr operr_store 181 bra not_enabled 182 183operr_byte: 184 moveql #1,%d1 |write size to d1 185 moveb STAG(%a6),%d0 |test stag for nan 186 andib #0xe0,%d0 |clr all but tag 187 cmpib #0x60,%d0 |check for nan 188 beqs operr_nan 189 cmpil #0xffffff80,FPTEMP_LO(%a6) |test if ls lword is special 190 bnes chkberr |if not equal, check for incorrect operr 191 bsr check_upper |check if exp and ms mant are special 192 tstl %d0 193 bnes chkberr |if d0 is true, check for incorrect operr 194 movel #0x80000000,%d0 |store special case result 195 bsr operr_store 196 bra not_enabled |clean and exit 197| 198| CHECK FOR INCORRECTLY GENERATED OPERR EXCEPTION HERE 199| 200chkberr: 201 movew FPTEMP_EX(%a6),%d0 202 andw #0x7FFF,%d0 |ignore sign bit 203 cmpw #0x3FFE,%d0 |this is the only possible exponent value 204 bnes store_max 205 movel FPTEMP_LO(%a6),%d0 206 asll #8,%d0 207 swap %d0 208 bsr operr_store 209 bra not_enabled 210 211| 212| This operr condition is not of the special case. Set operr 213| and aiop and write the portion of the nan to memory for the 214| given size. 215| 216operr_nan: 217 orl #opaop_mask,USER_FPSR(%a6) |set operr & aiop 218 219 movel ETEMP_HI(%a6),%d0 |output will be from upper 32 bits 220 bsr operr_store 221 bra end_operr 222| 223| Store_max loads the max pos or negative for the size, sets 224| the operr and aiop bits, and clears inex and ainex, incorrectly 225| set by the 040. 226| 227store_max: 228 orl #opaop_mask,USER_FPSR(%a6) |set operr & aiop 229 bclrb #inex2_bit,FPSR_EXCEPT(%a6) 230 bclrb #ainex_bit,FPSR_AEXCEPT(%a6) 231 fmovel #0,%FPSR 232 233 tstw FPTEMP_EX(%a6) |check sign 234 blts load_neg 235 movel #0x7fffffff,%d0 236 bsr operr_store 237 bra end_operr 238load_neg: 239 movel #0x80000000,%d0 240 bsr operr_store 241 bra end_operr 242 243| 244| This routine stores the data in d0, for the given size in d1, 245| to memory or data register as required. A read of the fline 246| is required to determine the destination. 247| 248operr_store: 249 movel %d0,L_SCR1(%a6) |move write data to L_SCR1 250 movel %d1,-(%a7) |save register size 251 bsrl get_fline |fline returned in d0 252 movel (%a7)+,%d1 253 bftst %d0{#26:#3} |if mode is zero, dest is Dn 254 bnes dest_mem 255| 256| Destination is Dn. Get register number from d0. Data is on 257| the stack at (a7). D1 has size: 1=byte,2=word,4=long/single 258| 259 andil #7,%d0 |isolate register number 260 cmpil #4,%d1 261 beqs op_long |the most frequent case 262 cmpil #2,%d1 263 bnes op_con 264 orl #8,%d0 265 bras op_con 266op_long: 267 orl #0x10,%d0 268op_con: 269 movel %d0,%d1 |format size:reg for reg_dest 270 bral reg_dest |call to reg_dest returns to caller 271| ;of operr_store 272| 273| Destination is memory. Get <ea> from integer exception frame 274| and call mem_write. 275| 276dest_mem: 277 leal L_SCR1(%a6),%a0 |put ptr to write data in a0 278 movel EXC_EA(%a6),%a1 |put user destination address in a1 279 movel %d1,%d0 |put size in d0 280 bsrl mem_write 281 rts 282| 283| Check the exponent for $c000 and the upper 32 bits of the 284| mantissa for $ffffffff. If both are true, return d0 clr 285| and store the lower n bits of the least lword of FPTEMP 286| to d0 for write out. If not, it is a real operr, and set d0. 287| 288check_upper: 289 cmpil #0xffffffff,FPTEMP_HI(%a6) |check if first byte is all 1's 290 bnes true_operr |if not all 1's then was true operr 291 cmpiw #0xc000,FPTEMP_EX(%a6) |check if incorrectly signalled 292 beqs not_true_operr |branch if not true operr 293 cmpiw #0xbfff,FPTEMP_EX(%a6) |check if incorrectly signalled 294 beqs not_true_operr |branch if not true operr 295true_operr: 296 movel #1,%d0 |signal real operr 297 rts 298not_true_operr: 299 clrl %d0 |signal no real operr 300 rts 301 302| 303| End_operr tests for operr enabled. If not, it cleans up the stack 304| and does an rte. If enabled, it cleans up the stack and branches 305| to the kernel operr handler with only the integer exception 306| frame on the stack and the fpu in the original exceptional state 307| with correct data written to the destination. 308| 309end_operr: 310 btstb #operr_bit,FPCR_ENABLE(%a6) 311 beqs not_enabled 312enabled: 313 moveml USER_DA(%a6),%d0-%d1/%a0-%a1 314 fmovemx USER_FP0(%a6),%fp0-%fp3 315 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar 316 frestore (%a7)+ 317 unlk %a6 318 bral real_operr 319 320not_enabled: 321| 322| It is possible to have either inex2 or inex1 exceptions with the 323| operr. If the inex enable bit is set in the FPCR, and either 324| inex2 or inex1 occurred, we must clean up and branch to the 325| real inex handler. 326| 327ck_inex: 328 moveb FPCR_ENABLE(%a6),%d0 329 andb FPSR_EXCEPT(%a6),%d0 330 andib #0x3,%d0 331 beq operr_exit 332| 333| Inexact enabled and reported, and we must take an inexact exception. 334| 335take_inex: 336 moveb #INEX_VEC,EXC_VEC+1(%a6) 337 movel USER_FPSR(%a6),FPSR_SHADOW(%a6) 338 orl #sx_mask,E_BYTE(%a6) 339 moveml USER_DA(%a6),%d0-%d1/%a0-%a1 340 fmovemx USER_FP0(%a6),%fp0-%fp3 341 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar 342 frestore (%a7)+ 343 unlk %a6 344 bral real_inex 345| 346| Since operr is only an E1 exception, there is no need to frestore 347| any state back to the fpu. 348| 349operr_exit: 350 moveml USER_DA(%a6),%d0-%d1/%a0-%a1 351 fmovemx USER_FP0(%a6),%fp0-%fp3 352 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar 353 unlk %a6 354 bral fpsp_done 355 356 |end 357