| | x_operr.sa 3.5 7/1/91 | | fpsp_operr --- FPSP handler for operand error exception | | See 68040 User's Manual pp. 9-44f | | Note 1: For trap disabled 040 does the following: | If the dest is a fp reg, then an extended precision non_signaling | NAN is stored in the dest reg. If the dest format is b, w, or l and | the source op is a NAN, then garbage is stored as the result (actually | the upper 32 bits of the mantissa are sent to the integer unit). If | the dest format is integer (b, w, l) and the operr is caused by | integer overflow, or the source op is inf, then the result stored is | garbage. | There are three cases in which operr is incorrectly signaled on the | 040. This occurs for move_out of format b, w, or l for the largest | negative integer (-2^7 for b, -2^15 for w, -2^31 for l). | | On opclass = 011 fmove.(b,w,l) that causes a conversion | overflow -> OPERR, the exponent in wbte (and fpte) is: | byte 56 - (62 - exp) | word 48 - (62 - exp) | long 32 - (62 - exp) | | where exp = (true exp) - 1 | | So, wbtemp and fptemp will contain the following on erroneously | signalled operr: | fpts = 1 | fpte = $4000 (15 bit externally) | byte fptm = $ffffffff ffffff80 | word fptm = $ffffffff ffff8000 | long fptm = $ffffffff 80000000 | | Note 2: For trap enabled 040 does the following: | If the inst is move_out, then same as Note 1. | If the inst is not move_out, the dest is not modified. | The exceptional operand is not defined for integer overflow | during a move_out. | | Copyright (C) Motorola, Inc. 1990 | All Rights Reserved | | THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA | The copyright notice above does not evidence any | actual or intended publication of such source code. X_OPERR: |idnt 2,1 | Motorola 040 Floating Point Software Package |section 8 #include "fpsp.h" |xref mem_write |xref real_operr |xref real_inex |xref get_fline |xref fpsp_done |xref reg_dest .global fpsp_operr fpsp_operr: | link %a6,#-LOCAL_SIZE fsave -(%a7) moveml %d0-%d1/%a0-%a1,USER_DA(%a6) fmovemx %fp0-%fp3,USER_FP0(%a6) fmoveml %fpcr/%fpsr/%fpiar,USER_FPCR(%a6) | | Check if this is an opclass 3 instruction. | If so, fall through, else branch to operr_end | btstb #TFLAG,T_BYTE(%a6) beqs operr_end | | If the destination size is B,W,or L, the operr must be | handled here. | movel CMDREG1B(%a6),%d0 bfextu %d0{#3:#3},%d0 |0=long, 4=word, 6=byte cmpib #0,%d0 |determine size; check long beq operr_long cmpib #4,%d0 |check word beq operr_word cmpib #6,%d0 |check byte beq operr_byte | | The size is not B,W,or L, so the operr is handled by the | kernel handler. Set the operr bits and clean up, leaving | only the integer exception frame on the stack, and the | fpu in the original exceptional state. | operr_end: bsetb #operr_bit,FPSR_EXCEPT(%a6) bsetb #aiop_bit,FPSR_AEXCEPT(%a6) moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar frestore (%a7)+ unlk %a6 bral real_operr operr_long: moveql #4,%d1 |write size to d1 moveb STAG(%a6),%d0 |test stag for nan andib #0xe0,%d0 |clr all but tag cmpib #0x60,%d0 |check for nan beq operr_nan cmpil #0x80000000,FPTEMP_LO(%a6) |test if ls lword is special bnes chklerr |if not equal, check for incorrect operr bsr check_upper |check if exp and ms mant are special tstl %d0 bnes chklerr |if d0 is true, check for incorrect operr movel #0x80000000,%d0 |store special case result bsr operr_store bra not_enabled |clean and exit | | CHECK FOR INCORRECTLY GENERATED OPERR EXCEPTION HERE | chklerr: movew FPTEMP_EX(%a6),%d0 andw #0x7FFF,%d0 |ignore sign bit cmpw #0x3FFE,%d0 |this is the only possible exponent value bnes chklerr2 fixlong: movel FPTEMP_LO(%a6),%d0 bsr operr_store bra not_enabled chklerr2: movew FPTEMP_EX(%a6),%d0 andw #0x7FFF,%d0 |ignore sign bit cmpw #0x4000,%d0 bcc store_max |exponent out of range movel FPTEMP_LO(%a6),%d0 andl #0x7FFF0000,%d0 |look for all 1's on bits 30-16 cmpl #0x7FFF0000,%d0 beqs fixlong tstl FPTEMP_LO(%a6) bpls chklepos cmpl #0xFFFFFFFF,FPTEMP_HI(%a6) beqs fixlong bra store_max chklepos: tstl FPTEMP_HI(%a6) beqs fixlong bra store_max operr_word: moveql #2,%d1 |write size to d1 moveb STAG(%a6),%d0 |test stag for nan andib #0xe0,%d0 |clr all but tag cmpib #0x60,%d0 |check for nan beq operr_nan cmpil #0xffff8000,FPTEMP_LO(%a6) |test if ls lword is special bnes chkwerr |if not equal, check for incorrect operr bsr check_upper |check if exp and ms mant are special tstl %d0 bnes chkwerr |if d0 is true, check for incorrect operr movel #0x80000000,%d0 |store special case result bsr operr_store bra not_enabled |clean and exit | | CHECK FOR INCORRECTLY GENERATED OPERR EXCEPTION HERE | chkwerr: movew FPTEMP_EX(%a6),%d0 andw #0x7FFF,%d0 |ignore sign bit cmpw #0x3FFE,%d0 |this is the only possible exponent value bnes store_max movel FPTEMP_LO(%a6),%d0 swap %d0 bsr operr_store bra not_enabled operr_byte: moveql #1,%d1 |write size to d1 moveb STAG(%a6),%d0 |test stag for nan andib #0xe0,%d0 |clr all but tag cmpib #0x60,%d0 |check for nan beqs operr_nan cmpil #0xffffff80,FPTEMP_LO(%a6) |test if ls lword is special bnes chkberr |if not equal, check for incorrect operr bsr check_upper |check if exp and ms mant are special tstl %d0 bnes chkberr |if d0 is true, check for incorrect operr movel #0x80000000,%d0 |store special case result bsr operr_store bra not_enabled |clean and exit | | CHECK FOR INCORRECTLY GENERATED OPERR EXCEPTION HERE | chkberr: movew FPTEMP_EX(%a6),%d0 andw #0x7FFF,%d0 |ignore sign bit cmpw #0x3FFE,%d0 |this is the only possible exponent value bnes store_max movel FPTEMP_LO(%a6),%d0 asll #8,%d0 swap %d0 bsr operr_store bra not_enabled | | This operr condition is not of the special case. Set operr | and aiop and write the portion of the nan to memory for the | given size. | operr_nan: orl #opaop_mask,USER_FPSR(%a6) |set operr & aiop movel ETEMP_HI(%a6),%d0 |output will be from upper 32 bits bsr operr_store bra end_operr | | Store_max loads the max pos or negative for the size, sets | the operr and aiop bits, and clears inex and ainex, incorrectly | set by the 040. | store_max: orl #opaop_mask,USER_FPSR(%a6) |set operr & aiop bclrb #inex2_bit,FPSR_EXCEPT(%a6) bclrb #ainex_bit,FPSR_AEXCEPT(%a6) fmovel #0,%FPSR tstw FPTEMP_EX(%a6) |check sign blts load_neg movel #0x7fffffff,%d0 bsr operr_store bra end_operr load_neg: movel #0x80000000,%d0 bsr operr_store bra end_operr | | This routine stores the data in d0, for the given size in d1, | to memory or data register as required. A read of the fline | is required to determine the destination. | operr_store: movel %d0,L_SCR1(%a6) |move write data to L_SCR1 movel %d1,-(%a7) |save register size bsrl get_fline |fline returned in d0 movel (%a7)+,%d1 bftst %d0{#26:#3} |if mode is zero, dest is Dn bnes dest_mem | | Destination is Dn. Get register number from d0. Data is on | the stack at (a7). D1 has size: 1=byte,2=word,4=long/single | andil #7,%d0 |isolate register number cmpil #4,%d1 beqs op_long |the most frequent case cmpil #2,%d1 bnes op_con orl #8,%d0 bras op_con op_long: orl #0x10,%d0 op_con: movel %d0,%d1 |format size:reg for reg_dest bral reg_dest |call to reg_dest returns to caller | ;of operr_store | | Destination is memory. Get from integer exception frame | and call mem_write. | dest_mem: leal L_SCR1(%a6),%a0 |put ptr to write data in a0 movel EXC_EA(%a6),%a1 |put user destination address in a1 movel %d1,%d0 |put size in d0 bsrl mem_write rts | | Check the exponent for $c000 and the upper 32 bits of the | mantissa for $ffffffff. If both are true, return d0 clr | and store the lower n bits of the least lword of FPTEMP | to d0 for write out. If not, it is a real operr, and set d0. | check_upper: cmpil #0xffffffff,FPTEMP_HI(%a6) |check if first byte is all 1's bnes true_operr |if not all 1's then was true operr cmpiw #0xc000,FPTEMP_EX(%a6) |check if incorrectly signalled beqs not_true_operr |branch if not true operr cmpiw #0xbfff,FPTEMP_EX(%a6) |check if incorrectly signalled beqs not_true_operr |branch if not true operr true_operr: movel #1,%d0 |signal real operr rts not_true_operr: clrl %d0 |signal no real operr rts | | End_operr tests for operr enabled. If not, it cleans up the stack | and does an rte. If enabled, it cleans up the stack and branches | to the kernel operr handler with only the integer exception | frame on the stack and the fpu in the original exceptional state | with correct data written to the destination. | end_operr: btstb #operr_bit,FPCR_ENABLE(%a6) beqs not_enabled enabled: moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar frestore (%a7)+ unlk %a6 bral real_operr not_enabled: | | It is possible to have either inex2 or inex1 exceptions with the | operr. If the inex enable bit is set in the FPCR, and either | inex2 or inex1 occurred, we must clean up and branch to the | real inex handler. | ck_inex: moveb FPCR_ENABLE(%a6),%d0 andb FPSR_EXCEPT(%a6),%d0 andib #0x3,%d0 beq operr_exit | | Inexact enabled and reported, and we must take an inexact exception. | take_inex: moveb #INEX_VEC,EXC_VEC+1(%a6) movel USER_FPSR(%a6),FPSR_SHADOW(%a6) orl #sx_mask,E_BYTE(%a6) moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar frestore (%a7)+ unlk %a6 bral real_inex | | Since operr is only an E1 exception, there is no need to frestore | any state back to the fpu. | operr_exit: moveml USER_DA(%a6),%d0-%d1/%a0-%a1 fmovemx USER_FP0(%a6),%fp0-%fp3 fmoveml USER_FPCR(%a6),%fpcr/%fpsr/%fpiar unlk %a6 bral fpsp_done |end