|
|
| get_op.sa 3.6 5/19/92
|
|
|
| get_op.sa 3.5 4/26/91
|
|
|
| Description: This routine is called by the unsupported format/data
|
| type exception handler ('unsupp' - vector 55) and the unimplemented
|
| instruction exception handler ('unimp' - vector 11). 'get_op'
|
| determines the opclass (0, 2, or 3) and branches to the
|
| opclass handler routine. See 68881/2 User's Manual table 4-11
|
| for a description of the opclasses.
|
|
|
| For UNSUPPORTED data/format (exception vector 55) and for
|
| UNIMPLEMENTED instructions (exception vector 11) the following
|
| applies:
|
|
|
| - For unnormalized numbers (opclass 0, 2, or 3) the
|
| number(s) is normalized and the operand type tag is updated.
|
|
|
| - For a packed number (opclass 2) the number is unpacked and the
|
| operand type tag is updated.
|
|
|
| - For denormalized numbers (opclass 0 or 2) the number(s) is not
|
| changed but passed to the next module. The next module for
|
| unimp is do_func, the next module for unsupp is res_func.
|
|
|
| For UNSUPPORTED data/format (exception vector 55) only the
|
| following applies:
|
|
|
| - If there is a move out with a packed number (opclass 3) the
|
| number is packed and written to user memory. For the other
|
| opclasses the number(s) are written back to the fsave stack
|
| and the instruction is then restored back into the '040. The
|
| '040 is then able to complete the instruction.
|
|
|
| For example:
|
| fadd.x fpm,fpn where the fpm contains an unnormalized number.
|
| The '040 takes an unsupported data trap and gets to this
|
| routine. The number is normalized, put back on the stack and
|
| then an frestore is done to restore the instruction back into
|
| the '040. The '040 then re-executes the fadd.x fpm,fpn with
|
| a normalized number in the source and the instruction is
|
| successful.
|
|
|
| Next consider if in the process of normalizing the un-
|
| normalized number it becomes a denormalized number. The
|
| routine which converts the unnorm to a norm (called mk_norm)
|
| detects this and tags the number as a denorm. The routine
|
| res_func sees the denorm tag and converts the denorm to a
|
| norm. The instruction is then restored back into the '040
|
| which re_executes the instruction.
|
|
|
|
|
| Copyright (C) Motorola, Inc. 1990
|
| All Rights Reserved
|
|
|
| For details on the license for this file, please see the
|
| file, README, in this same directory.
|
|
GET_OP: |idnt 2,1 | Motorola 040 Floating Point Software Package
|
|
|section 8
|
|
#include "fpsp.h"
|
|
.global PIRN,PIRZRM,PIRP
|
.global SMALRN,SMALRZRM,SMALRP
|
.global BIGRN,BIGRZRM,BIGRP
|
|
PIRN:
|
.long 0x40000000,0xc90fdaa2,0x2168c235 |pi
|
PIRZRM:
|
.long 0x40000000,0xc90fdaa2,0x2168c234 |pi
|
PIRP:
|
.long 0x40000000,0xc90fdaa2,0x2168c235 |pi
|
|
|round to nearest
|
SMALRN:
|
.long 0x3ffd0000,0x9a209a84,0xfbcff798 |log10(2)
|
.long 0x40000000,0xadf85458,0xa2bb4a9a |e
|
.long 0x3fff0000,0xb8aa3b29,0x5c17f0bc |log2(e)
|
.long 0x3ffd0000,0xde5bd8a9,0x37287195 |log10(e)
|
.long 0x00000000,0x00000000,0x00000000 |0.0
|
| round to zero;round to negative infinity
|
SMALRZRM:
|
.long 0x3ffd0000,0x9a209a84,0xfbcff798 |log10(2)
|
.long 0x40000000,0xadf85458,0xa2bb4a9a |e
|
.long 0x3fff0000,0xb8aa3b29,0x5c17f0bb |log2(e)
|
.long 0x3ffd0000,0xde5bd8a9,0x37287195 |log10(e)
|
.long 0x00000000,0x00000000,0x00000000 |0.0
|
| round to positive infinity
|
SMALRP:
|
.long 0x3ffd0000,0x9a209a84,0xfbcff799 |log10(2)
|
.long 0x40000000,0xadf85458,0xa2bb4a9b |e
|
.long 0x3fff0000,0xb8aa3b29,0x5c17f0bc |log2(e)
|
.long 0x3ffd0000,0xde5bd8a9,0x37287195 |log10(e)
|
.long 0x00000000,0x00000000,0x00000000 |0.0
|
|
|round to nearest
|
BIGRN:
|
.long 0x3ffe0000,0xb17217f7,0xd1cf79ac |ln(2)
|
.long 0x40000000,0x935d8ddd,0xaaa8ac17 |ln(10)
|
.long 0x3fff0000,0x80000000,0x00000000 |10 ^ 0
|
|
.global PTENRN
|
PTENRN:
|
.long 0x40020000,0xA0000000,0x00000000 |10 ^ 1
|
.long 0x40050000,0xC8000000,0x00000000 |10 ^ 2
|
.long 0x400C0000,0x9C400000,0x00000000 |10 ^ 4
|
.long 0x40190000,0xBEBC2000,0x00000000 |10 ^ 8
|
.long 0x40340000,0x8E1BC9BF,0x04000000 |10 ^ 16
|
.long 0x40690000,0x9DC5ADA8,0x2B70B59E |10 ^ 32
|
.long 0x40D30000,0xC2781F49,0xFFCFA6D5 |10 ^ 64
|
.long 0x41A80000,0x93BA47C9,0x80E98CE0 |10 ^ 128
|
.long 0x43510000,0xAA7EEBFB,0x9DF9DE8E |10 ^ 256
|
.long 0x46A30000,0xE319A0AE,0xA60E91C7 |10 ^ 512
|
.long 0x4D480000,0xC9767586,0x81750C17 |10 ^ 1024
|
.long 0x5A920000,0x9E8B3B5D,0xC53D5DE5 |10 ^ 2048
|
.long 0x75250000,0xC4605202,0x8A20979B |10 ^ 4096
|
|round to minus infinity
|
BIGRZRM:
|
.long 0x3ffe0000,0xb17217f7,0xd1cf79ab |ln(2)
|
.long 0x40000000,0x935d8ddd,0xaaa8ac16 |ln(10)
|
.long 0x3fff0000,0x80000000,0x00000000 |10 ^ 0
|
|
.global PTENRM
|
PTENRM:
|
.long 0x40020000,0xA0000000,0x00000000 |10 ^ 1
|
.long 0x40050000,0xC8000000,0x00000000 |10 ^ 2
|
.long 0x400C0000,0x9C400000,0x00000000 |10 ^ 4
|
.long 0x40190000,0xBEBC2000,0x00000000 |10 ^ 8
|
.long 0x40340000,0x8E1BC9BF,0x04000000 |10 ^ 16
|
.long 0x40690000,0x9DC5ADA8,0x2B70B59D |10 ^ 32
|
.long 0x40D30000,0xC2781F49,0xFFCFA6D5 |10 ^ 64
|
.long 0x41A80000,0x93BA47C9,0x80E98CDF |10 ^ 128
|
.long 0x43510000,0xAA7EEBFB,0x9DF9DE8D |10 ^ 256
|
.long 0x46A30000,0xE319A0AE,0xA60E91C6 |10 ^ 512
|
.long 0x4D480000,0xC9767586,0x81750C17 |10 ^ 1024
|
.long 0x5A920000,0x9E8B3B5D,0xC53D5DE5 |10 ^ 2048
|
.long 0x75250000,0xC4605202,0x8A20979A |10 ^ 4096
|
|round to positive infinity
|
BIGRP:
|
.long 0x3ffe0000,0xb17217f7,0xd1cf79ac |ln(2)
|
.long 0x40000000,0x935d8ddd,0xaaa8ac17 |ln(10)
|
.long 0x3fff0000,0x80000000,0x00000000 |10 ^ 0
|
|
.global PTENRP
|
PTENRP:
|
.long 0x40020000,0xA0000000,0x00000000 |10 ^ 1
|
.long 0x40050000,0xC8000000,0x00000000 |10 ^ 2
|
.long 0x400C0000,0x9C400000,0x00000000 |10 ^ 4
|
.long 0x40190000,0xBEBC2000,0x00000000 |10 ^ 8
|
.long 0x40340000,0x8E1BC9BF,0x04000000 |10 ^ 16
|
.long 0x40690000,0x9DC5ADA8,0x2B70B59E |10 ^ 32
|
.long 0x40D30000,0xC2781F49,0xFFCFA6D6 |10 ^ 64
|
.long 0x41A80000,0x93BA47C9,0x80E98CE0 |10 ^ 128
|
.long 0x43510000,0xAA7EEBFB,0x9DF9DE8E |10 ^ 256
|
.long 0x46A30000,0xE319A0AE,0xA60E91C7 |10 ^ 512
|
.long 0x4D480000,0xC9767586,0x81750C18 |10 ^ 1024
|
.long 0x5A920000,0x9E8B3B5D,0xC53D5DE6 |10 ^ 2048
|
.long 0x75250000,0xC4605202,0x8A20979B |10 ^ 4096
|
|
|xref nrm_zero
|
|xref decbin
|
|xref round
|
|
.global get_op
|
.global uns_getop
|
.global uni_getop
|
get_op:
|
clrb DY_MO_FLG(%a6)
|
tstb UFLG_TMP(%a6) |test flag for unsupp/unimp state
|
beq uni_getop
|
|
uns_getop:
|
btstb #direction_bit,CMDREG1B(%a6)
|
bne opclass3 |branch if a fmove out (any kind)
|
btstb #6,CMDREG1B(%a6)
|
beqs uns_notpacked
|
|
bfextu CMDREG1B(%a6){#3:#3},%d0
|
cmpb #3,%d0
|
beq pack_source |check for a packed src op, branch if so
|
uns_notpacked:
|
bsr chk_dy_mo |set the dyadic/monadic flag
|
tstb DY_MO_FLG(%a6)
|
beqs src_op_ck |if monadic, go check src op
|
| ;else, check dst op (fall through)
|
|
btstb #7,DTAG(%a6)
|
beqs src_op_ck |if dst op is norm, check src op
|
bras dst_ex_dnrm |else, handle destination unnorm/dnrm
|
|
uni_getop:
|
bfextu CMDREG1B(%a6){#0:#6},%d0 |get opclass and src fields
|
cmpil #0x17,%d0 |if op class and size fields are $17,
|
| ;it is FMOVECR; if not, continue
|
|
|
| If the instruction is fmovecr, exit get_op. It is handled
|
| in do_func and smovecr.sa.
|
|
|
bne not_fmovecr |handle fmovecr as an unimplemented inst
|
rts
|
|
not_fmovecr:
|
btstb #E1,E_BYTE(%a6) |if set, there is a packed operand
|
bne pack_source |check for packed src op, branch if so
|
|
| The following lines of are coded to optimize on normalized operands
|
moveb STAG(%a6),%d0
|
orb DTAG(%a6),%d0 |check if either of STAG/DTAG msb set
|
bmis dest_op_ck |if so, some op needs to be fixed
|
rts
|
|
dest_op_ck:
|
btstb #7,DTAG(%a6) |check for unsupported data types in
|
beqs src_op_ck |the destination, if not, check src op
|
bsr chk_dy_mo |set dyadic/monadic flag
|
tstb DY_MO_FLG(%a6) |
|
beqs src_op_ck |if monadic, check src op
|
|
|
| At this point, destination has an extended denorm or unnorm.
|
|
|
dst_ex_dnrm:
|
movew FPTEMP_EX(%a6),%d0 |get destination exponent
|
andiw #0x7fff,%d0 |mask sign, check if exp = 0000
|
beqs src_op_ck |if denorm then check source op.
|
| ;denorms are taken care of in res_func
|
| ;(unsupp) or do_func (unimp)
|
| ;else unnorm fall through
|
leal FPTEMP(%a6),%a0 |point a0 to dop - used in mk_norm
|
bsr mk_norm |go normalize - mk_norm returns:
|
| ;L_SCR1{7:5} = operand tag
|
| ; (000 = norm, 100 = denorm)
|
| ;L_SCR1{4} = fpte15 or ete15
|
| ; 0 = exp > $3fff
|
| ; 1 = exp <= $3fff
|
| ;and puts the normalized num back
|
| ;on the fsave stack
|
|
|
moveb L_SCR1(%a6),DTAG(%a6) |write the new tag & fpte15
|
| ;to the fsave stack and fall
|
| ;through to check source operand
|
|
|
src_op_ck:
|
btstb #7,STAG(%a6)
|
beq end_getop |check for unsupported data types on the
|
| ;source operand
|
btstb #5,STAG(%a6)
|
bnes src_sd_dnrm |if bit 5 set, handle sgl/dbl denorms
|
|
|
| At this point only unnorms or extended denorms are possible.
|
|
|
src_ex_dnrm:
|
movew ETEMP_EX(%a6),%d0 |get source exponent
|
andiw #0x7fff,%d0 |mask sign, check if exp = 0000
|
beq end_getop |if denorm then exit, denorms are
|
| ;handled in do_func
|
leal ETEMP(%a6),%a0 |point a0 to sop - used in mk_norm
|
bsr mk_norm |go normalize - mk_norm returns:
|
| ;L_SCR1{7:5} = operand tag
|
| ; (000 = norm, 100 = denorm)
|
| ;L_SCR1{4} = fpte15 or ete15
|
| ; 0 = exp > $3fff
|
| ; 1 = exp <= $3fff
|
| ;and puts the normalized num back
|
| ;on the fsave stack
|
|
|
moveb L_SCR1(%a6),STAG(%a6) |write the new tag & ete15
|
rts |end_getop
|
|
|
|
| At this point, only single or double denorms are possible.
|
| If the inst is not fmove, normalize the source. If it is,
|
| do nothing to the input.
|
|
|
src_sd_dnrm:
|
btstb #4,CMDREG1B(%a6) |differentiate between sgl/dbl denorm
|
bnes is_double
|
is_single:
|
movew #0x3f81,%d1 |write bias for sgl denorm
|
bras common |goto the common code
|
is_double:
|
movew #0x3c01,%d1 |write the bias for a dbl denorm
|
common:
|
btstb #sign_bit,ETEMP_EX(%a6) |grab sign bit of mantissa
|
beqs pos
|
bset #15,%d1 |set sign bit because it is negative
|
pos:
|
movew %d1,ETEMP_EX(%a6)
|
| ;put exponent on stack
|
|
movew CMDREG1B(%a6),%d1
|
andw #0xe3ff,%d1 |clear out source specifier
|
orw #0x0800,%d1 |set source specifier to extended prec
|
movew %d1,CMDREG1B(%a6) |write back to the command word in stack
|
| ;this is needed to fix unsupp data stack
|
leal ETEMP(%a6),%a0 |point a0 to sop
|
|
bsr mk_norm |convert sgl/dbl denorm to norm
|
moveb L_SCR1(%a6),STAG(%a6) |put tag into source tag reg - d0
|
rts |end_getop
|
|
|
| At this point, the source is definitely packed, whether
|
| instruction is dyadic or monadic is still unknown
|
|
|
pack_source:
|
movel FPTEMP_LO(%a6),ETEMP(%a6) |write ms part of packed
|
| ;number to etemp slot
|
bsr chk_dy_mo |set dyadic/monadic flag
|
bsr unpack
|
|
tstb DY_MO_FLG(%a6)
|
beqs end_getop |if monadic, exit
|
| ;else, fix FPTEMP
|
pack_dya:
|
bfextu CMDREG1B(%a6){#6:#3},%d0 |extract dest fp reg
|
movel #7,%d1
|
subl %d0,%d1
|
clrl %d0
|
bsetl %d1,%d0 |set up d0 as a dynamic register mask
|
fmovemx %d0,FPTEMP(%a6) |write to FPTEMP
|
|
btstb #7,DTAG(%a6) |check dest tag for unnorm or denorm
|
bne dst_ex_dnrm |else, handle the unnorm or ext denorm
|
|
|
| Dest is not denormalized. Check for norm, and set fpte15
|
| accordingly.
|
|
|
moveb DTAG(%a6),%d0
|
andib #0xf0,%d0 |strip to only dtag:fpte15
|
tstb %d0 |check for normalized value
|
bnes end_getop |if inf/nan/zero leave get_op
|
movew FPTEMP_EX(%a6),%d0
|
andiw #0x7fff,%d0
|
cmpiw #0x3fff,%d0 |check if fpte15 needs setting
|
bges end_getop |if >= $3fff, leave fpte15=0
|
orb #0x10,DTAG(%a6)
|
bras end_getop
|
|
|
|
| At this point, it is either an fmoveout packed, unnorm or denorm
|
|
|
opclass3:
|
clrb DY_MO_FLG(%a6) |set dyadic/monadic flag to monadic
|
bfextu CMDREG1B(%a6){#4:#2},%d0
|
cmpib #3,%d0
|
bne src_ex_dnrm |if not equal, must be unnorm or denorm
|
| ;else it is a packed move out
|
| ;exit
|
end_getop:
|
rts
|
|
|
|
| Sets the DY_MO_FLG correctly. This is used only on if it is an
|
| unsupported data type exception. Set if dyadic.
|
|
|
chk_dy_mo:
|
movew CMDREG1B(%a6),%d0
|
btstl #5,%d0 |testing extension command word
|
beqs set_mon |if bit 5 = 0 then monadic
|
btstl #4,%d0 |know that bit 5 = 1
|
beqs set_dya |if bit 4 = 0 then dyadic
|
andiw #0x007f,%d0 |get rid of all but extension bits {6:0}
|
cmpiw #0x0038,%d0 |if extension = $38 then fcmp (dyadic)
|
bnes set_mon
|
set_dya:
|
st DY_MO_FLG(%a6) |set the inst flag type to dyadic
|
rts
|
set_mon:
|
clrb DY_MO_FLG(%a6) |set the inst flag type to monadic
|
rts
|
|
|
| MK_NORM
|
|
|
| Normalizes unnormalized numbers, sets tag to norm or denorm, sets unfl
|
| exception if denorm.
|
|
|
| CASE opclass 0x0 unsupp
|
| mk_norm till msb set
|
| set tag = norm
|
|
|
| CASE opclass 0x0 unimp
|
| mk_norm till msb set or exp = 0
|
| if integer bit = 0
|
| tag = denorm
|
| else
|
| tag = norm
|
|
|
| CASE opclass 011 unsupp
|
| mk_norm till msb set or exp = 0
|
| if integer bit = 0
|
| tag = denorm
|
| set unfl_nmcexe = 1
|
| else
|
| tag = norm
|
|
|
| if exp <= $3fff
|
| set ete15 or fpte15 = 1
|
| else set ete15 or fpte15 = 0
|
|
| input:
|
| a0 = points to operand to be normalized
|
| output:
|
| L_SCR1{7:5} = operand tag (000 = norm, 100 = denorm)
|
| L_SCR1{4} = fpte15 or ete15 (0 = exp > $3fff, 1 = exp <=$3fff)
|
| the normalized operand is placed back on the fsave stack
|
mk_norm:
|
clrl L_SCR1(%a6)
|
bclrb #sign_bit,LOCAL_EX(%a0)
|
sne LOCAL_SGN(%a0) |transform into internal extended format
|
|
cmpib #0x2c,1+EXC_VEC(%a6) |check if unimp
|
bnes uns_data |branch if unsupp
|
bsr uni_inst |call if unimp (opclass 0x0)
|
bras reload
|
uns_data:
|
btstb #direction_bit,CMDREG1B(%a6) |check transfer direction
|
bnes bit_set |branch if set (opclass 011)
|
bsr uns_opx |call if opclass 0x0
|
bras reload
|
bit_set:
|
bsr uns_op3 |opclass 011
|
reload:
|
cmpw #0x3fff,LOCAL_EX(%a0) |if exp > $3fff
|
bgts end_mk | fpte15/ete15 already set to 0
|
bsetb #4,L_SCR1(%a6) |else set fpte15/ete15 to 1
|
| ;calling routine actually sets the
|
| ;value on the stack (along with the
|
| ;tag), since this routine doesn't
|
| ;know if it should set ete15 or fpte15
|
| ;ie, it doesn't know if this is the
|
| ;src op or dest op.
|
end_mk:
|
bfclr LOCAL_SGN(%a0){#0:#8}
|
beqs end_mk_pos
|
bsetb #sign_bit,LOCAL_EX(%a0) |convert back to IEEE format
|
end_mk_pos:
|
rts
|
|
|
| CASE opclass 011 unsupp
|
|
|
uns_op3:
|
bsr nrm_zero |normalize till msb = 1 or exp = zero
|
btstb #7,LOCAL_HI(%a0) |if msb = 1
|
bnes no_unfl |then branch
|
set_unfl:
|
orw #dnrm_tag,L_SCR1(%a6) |set denorm tag
|
bsetb #unfl_bit,FPSR_EXCEPT(%a6) |set unfl exception bit
|
no_unfl:
|
rts
|
|
|
| CASE opclass 0x0 unsupp
|
|
|
uns_opx:
|
bsr nrm_zero |normalize the number
|
btstb #7,LOCAL_HI(%a0) |check if integer bit (j-bit) is set
|
beqs uns_den |if clear then now have a denorm
|
uns_nrm:
|
orb #norm_tag,L_SCR1(%a6) |set tag to norm
|
rts
|
uns_den:
|
orb #dnrm_tag,L_SCR1(%a6) |set tag to denorm
|
rts
|
|
|
| CASE opclass 0x0 unimp
|
|
|
uni_inst:
|
bsr nrm_zero
|
btstb #7,LOCAL_HI(%a0) |check if integer bit (j-bit) is set
|
beqs uni_den |if clear then now have a denorm
|
uni_nrm:
|
orb #norm_tag,L_SCR1(%a6) |set tag to norm
|
rts
|
uni_den:
|
orb #dnrm_tag,L_SCR1(%a6) |set tag to denorm
|
rts
|
|
|
|
| Decimal to binary conversion
|
|
|
| Special cases of inf and NaNs are completed outside of decbin.
|
| If the input is an snan, the snan bit is not set.
|
|
|
| input:
|
| ETEMP(a6) - points to packed decimal string in memory
|
| output:
|
| fp0 - contains packed string converted to extended precision
|
| ETEMP - same as fp0
|
unpack:
|
movew CMDREG1B(%a6),%d0 |examine command word, looking for fmove's
|
andw #0x3b,%d0
|
beq move_unpack |special handling for fmove: must set FPSR_CC
|
|
movew ETEMP(%a6),%d0 |get word with inf information
|
bfextu %d0{#20:#12},%d1 |get exponent into d1
|
cmpiw #0x0fff,%d1 |test for inf or NaN
|
bnes try_zero |if not equal, it is not special
|
bfextu %d0{#17:#3},%d1 |get SE and y bits into d1
|
cmpiw #7,%d1 |SE and y bits must be on for special
|
bnes try_zero |if not on, it is not special
|
|input is of the special cases of inf and NaN
|
tstl ETEMP_HI(%a6) |check ms mantissa
|
bnes fix_nan |if non-zero, it is a NaN
|
tstl ETEMP_LO(%a6) |check ls mantissa
|
bnes fix_nan |if non-zero, it is a NaN
|
bra finish |special already on stack
|
fix_nan:
|
btstb #signan_bit,ETEMP_HI(%a6) |test for snan
|
bne finish
|
orl #snaniop_mask,USER_FPSR(%a6) |always set snan if it is so
|
bra finish
|
try_zero:
|
movew ETEMP_EX+2(%a6),%d0 |get word 4
|
andiw #0x000f,%d0 |clear all but last ni(y)bble
|
tstw %d0 |check for zero.
|
bne not_spec
|
tstl ETEMP_HI(%a6) |check words 3 and 2
|
bne not_spec
|
tstl ETEMP_LO(%a6) |check words 1 and 0
|
bne not_spec
|
tstl ETEMP(%a6) |test sign of the zero
|
bges pos_zero
|
movel #0x80000000,ETEMP(%a6) |write neg zero to etemp
|
clrl ETEMP_HI(%a6)
|
clrl ETEMP_LO(%a6)
|
bra finish
|
pos_zero:
|
clrl ETEMP(%a6)
|
clrl ETEMP_HI(%a6)
|
clrl ETEMP_LO(%a6)
|
bra finish
|
|
not_spec:
|
fmovemx %fp0-%fp1,-(%a7) |save fp0 - decbin returns in it
|
bsr decbin
|
fmovex %fp0,ETEMP(%a6) |put the unpacked sop in the fsave stack
|
fmovemx (%a7)+,%fp0-%fp1
|
fmovel #0,%FPSR |clr fpsr from decbin
|
bra finish
|
|
|
|
| Special handling for packed move in: Same results as all other
|
| packed cases, but we must set the FPSR condition codes properly.
|
|
|
move_unpack:
|
movew ETEMP(%a6),%d0 |get word with inf information
|
bfextu %d0{#20:#12},%d1 |get exponent into d1
|
cmpiw #0x0fff,%d1 |test for inf or NaN
|
bnes mtry_zero |if not equal, it is not special
|
bfextu %d0{#17:#3},%d1 |get SE and y bits into d1
|
cmpiw #7,%d1 |SE and y bits must be on for special
|
bnes mtry_zero |if not on, it is not special
|
|input is of the special cases of inf and NaN
|
tstl ETEMP_HI(%a6) |check ms mantissa
|
bnes mfix_nan |if non-zero, it is a NaN
|
tstl ETEMP_LO(%a6) |check ls mantissa
|
bnes mfix_nan |if non-zero, it is a NaN
|
|input is inf
|
orl #inf_mask,USER_FPSR(%a6) |set I bit
|
tstl ETEMP(%a6) |check sign
|
bge finish
|
orl #neg_mask,USER_FPSR(%a6) |set N bit
|
bra finish |special already on stack
|
mfix_nan:
|
orl #nan_mask,USER_FPSR(%a6) |set NaN bit
|
moveb #nan_tag,STAG(%a6) |set stag to NaN
|
btstb #signan_bit,ETEMP_HI(%a6) |test for snan
|
bnes mn_snan
|
orl #snaniop_mask,USER_FPSR(%a6) |set snan bit
|
btstb #snan_bit,FPCR_ENABLE(%a6) |test for snan enabled
|
bnes mn_snan
|
bsetb #signan_bit,ETEMP_HI(%a6) |force snans to qnans
|
mn_snan:
|
tstl ETEMP(%a6) |check for sign
|
bge finish |if clr, go on
|
orl #neg_mask,USER_FPSR(%a6) |set N bit
|
bra finish
|
|
mtry_zero:
|
movew ETEMP_EX+2(%a6),%d0 |get word 4
|
andiw #0x000f,%d0 |clear all but last ni(y)bble
|
tstw %d0 |check for zero.
|
bnes mnot_spec
|
tstl ETEMP_HI(%a6) |check words 3 and 2
|
bnes mnot_spec
|
tstl ETEMP_LO(%a6) |check words 1 and 0
|
bnes mnot_spec
|
tstl ETEMP(%a6) |test sign of the zero
|
bges mpos_zero
|
orl #neg_mask+z_mask,USER_FPSR(%a6) |set N and Z
|
movel #0x80000000,ETEMP(%a6) |write neg zero to etemp
|
clrl ETEMP_HI(%a6)
|
clrl ETEMP_LO(%a6)
|
bras finish
|
mpos_zero:
|
orl #z_mask,USER_FPSR(%a6) |set Z
|
clrl ETEMP(%a6)
|
clrl ETEMP_HI(%a6)
|
clrl ETEMP_LO(%a6)
|
bras finish
|
|
mnot_spec:
|
fmovemx %fp0-%fp1,-(%a7) |save fp0 ,fp1 - decbin returns in fp0
|
bsr decbin
|
fmovex %fp0,ETEMP(%a6)
|
| ;put the unpacked sop in the fsave stack
|
fmovemx (%a7)+,%fp0-%fp1
|
|
finish:
|
movew CMDREG1B(%a6),%d0 |get the command word
|
andw #0xfbff,%d0 |change the source specifier field to
|
| ;extended (was packed).
|
movew %d0,CMDREG1B(%a6) |write command word back to fsave stack
|
| ;we need to do this so the 040 will
|
| ;re-execute the inst. without taking
|
| ;another packed trap.
|
|
fix_stag:
|
|Converted result is now in etemp on fsave stack, now set the source
|
|tag (stag)
|
| if (ete =$7fff) then INF or NAN
|
| if (etemp = $x.0----0) then
|
| stag = INF
|
| else
|
| stag = NAN
|
| else
|
| if (ete = $0000) then
|
| stag = ZERO
|
| else
|
| stag = NORM
|
|
|
| Note also that the etemp_15 bit (just right of the stag) must
|
| be set accordingly.
|
|
|
movew ETEMP_EX(%a6),%d1
|
andiw #0x7fff,%d1 |strip sign
|
cmpw #0x7fff,%d1
|
bnes z_or_nrm
|
movel ETEMP_HI(%a6),%d1
|
bnes is_nan
|
movel ETEMP_LO(%a6),%d1
|
bnes is_nan
|
is_inf:
|
moveb #0x40,STAG(%a6)
|
movel #0x40,%d0
|
rts
|
is_nan:
|
moveb #0x60,STAG(%a6)
|
movel #0x60,%d0
|
rts
|
z_or_nrm:
|
tstw %d1
|
bnes is_nrm
|
is_zro:
|
| For a zero, set etemp_15
|
moveb #0x30,STAG(%a6)
|
movel #0x20,%d0
|
rts
|
is_nrm:
|
| For a norm, check if the exp <= $3fff; if so, set etemp_15
|
cmpiw #0x3fff,%d1
|
bles set_bit15
|
moveb #0,STAG(%a6)
|
bras end_is_nrm
|
set_bit15:
|
moveb #0x10,STAG(%a6)
|
end_is_nrm:
|
movel #0,%d0
|
end_fix:
|
rts
|
|
end_get:
|
rts
|
|end
|
