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