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res_func.S
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|
| res_func.sa 3.9 7/29/91
|
| Normalizes denormalized numbers if necessary and updates the
| stack frame. The function is then restored back into the
| machine and the 040 completes the operation. This routine
| is only used by the unsupported data type/format handler.
| (Exception vector 55).
|
| For packed move out (fmove.p fpm,<ea>) the operation is
| completed here; data is packed and moved to user memory.
| The stack is restored to the 040 only in the case of a
| reportable exception in the conversion.
|
|
| 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.
RES_FUNC: |idnt 2,1 | Motorola 040 Floating Point Software Package
|section 8
#include "fpsp.h"
sp_bnds: .short 0x3f81,0x407e
.short 0x3f6a,0x0000
dp_bnds: .short 0x3c01,0x43fe
.short 0x3bcd,0x0000
|xref mem_write
|xref bindec
|xref get_fline
|xref round
|xref denorm
|xref dest_ext
|xref dest_dbl
|xref dest_sgl
|xref unf_sub
|xref nrm_set
|xref dnrm_lp
|xref ovf_res
|xref reg_dest
|xref t_ovfl
|xref t_unfl
.global res_func
.global p_move
res_func:
clrb DNRM_FLG(%a6)
clrb RES_FLG(%a6)
clrb CU_ONLY(%a6)
tstb DY_MO_FLG(%a6)
beqs monadic
dyadic:
btstb #7,DTAG(%a6) |if dop = norm=000, zero=001,
| ;inf=010 or nan=011
beqs monadic |then branch
| ;else denorm
| HANDLE DESTINATION DENORM HERE
| ;set dtag to norm
| ;write the tag & fpte15 to the fstack
leal FPTEMP(%a6),%a0
bclrb #sign_bit,LOCAL_EX(%a0)
sne LOCAL_SGN(%a0)
bsr nrm_set |normalize number (exp will go negative)
bclrb #sign_bit,LOCAL_EX(%a0) |get rid of false sign
bfclr LOCAL_SGN(%a0){#0:#8} |change back to IEEE ext format
beqs dpos
bsetb #sign_bit,LOCAL_EX(%a0)
dpos:
bfclr DTAG(%a6){#0:#4} |set tag to normalized, FPTE15 = 0
bsetb #4,DTAG(%a6) |set FPTE15
orb #0x0f,DNRM_FLG(%a6)
monadic:
leal ETEMP(%a6),%a0
btstb #direction_bit,CMDREG1B(%a6) |check direction
bne opclass3 |it is a mv out
|
| At this point, only opclass 0 and 2 possible
|
btstb #7,STAG(%a6) |if sop = norm=000, zero=001,
| ;inf=010 or nan=011
bne mon_dnrm |else denorm
tstb DY_MO_FLG(%a6) |all cases of dyadic instructions would
bne normal |require normalization of denorm
| At this point:
| monadic instructions: fabs = $18 fneg = $1a ftst = $3a
| fmove = $00 fsmove = $40 fdmove = $44
| fsqrt = $05* fssqrt = $41 fdsqrt = $45
| (*fsqrt reencoded to $05)
|
movew CMDREG1B(%a6),%d0 |get command register
andil #0x7f,%d0 |strip to only command word
|
| At this point, fabs, fneg, fsmove, fdmove, ftst, fsqrt, fssqrt, and
| fdsqrt are possible.
| For cases fabs, fneg, fsmove, and fdmove goto spos (do not normalize)
| For cases fsqrt, fssqrt, and fdsqrt goto nrm_src (do normalize)
|
btstl #0,%d0
bne normal |weed out fsqrt instructions
|
| cu_norm handles fmove in instructions with normalized inputs.
| The routine round is used to correctly round the input for the
| destination precision and mode.
|
cu_norm:
st CU_ONLY(%a6) |set cu-only inst flag
movew CMDREG1B(%a6),%d0
andib #0x3b,%d0 |isolate bits to select inst
tstb %d0
beql cu_nmove |if zero, it is an fmove
cmpib #0x18,%d0
beql cu_nabs |if $18, it is fabs
cmpib #0x1a,%d0
beql cu_nneg |if $1a, it is fneg
|
| Inst is ftst. Check the source operand and set the cc's accordingly.
| No write is done, so simply rts.
|
cu_ntst:
movew LOCAL_EX(%a0),%d0
bclrl #15,%d0
sne LOCAL_SGN(%a0)
beqs cu_ntpo
orl #neg_mask,USER_FPSR(%a6) |set N
cu_ntpo:
cmpiw #0x7fff,%d0 |test for inf/nan
bnes cu_ntcz
tstl LOCAL_HI(%a0)
bnes cu_ntn
tstl LOCAL_LO(%a0)
bnes cu_ntn
orl #inf_mask,USER_FPSR(%a6)
rts
cu_ntn:
orl #nan_mask,USER_FPSR(%a6)
movel ETEMP_EX(%a6),FPTEMP_EX(%a6) |set up fptemp sign for
| ;snan handler
rts
cu_ntcz:
tstl LOCAL_HI(%a0)
bnel cu_ntsx
tstl LOCAL_LO(%a0)
bnel cu_ntsx
orl #z_mask,USER_FPSR(%a6)
cu_ntsx:
rts
|
| Inst is fabs. Execute the absolute value function on the input.
| Branch to the fmove code. If the operand is NaN, do nothing.
|
cu_nabs:
moveb STAG(%a6),%d0
btstl #5,%d0 |test for NaN or zero
bne wr_etemp |if either, simply write it
bclrb #7,LOCAL_EX(%a0) |do abs
bras cu_nmove |fmove code will finish
|
| Inst is fneg. Execute the negate value function on the input.
| Fall though to the fmove code. If the operand is NaN, do nothing.
|
cu_nneg:
moveb STAG(%a6),%d0
btstl #5,%d0 |test for NaN or zero
bne wr_etemp |if either, simply write it
bchgb #7,LOCAL_EX(%a0) |do neg
|
| Inst is fmove. This code also handles all result writes.
| If bit 2 is set, round is forced to double. If it is clear,
| and bit 6 is set, round is forced to single. If both are clear,
| the round precision is found in the fpcr. If the rounding precision
| is double or single, round the result before the write.
|
cu_nmove:
moveb STAG(%a6),%d0
andib #0xe0,%d0 |isolate stag bits
bne wr_etemp |if not norm, simply write it
btstb #2,CMDREG1B+1(%a6) |check for rd
bne cu_nmrd
btstb #6,CMDREG1B+1(%a6) |check for rs
bne cu_nmrs
|
| The move or operation is not with forced precision. Test for
| nan or inf as the input; if so, simply write it to FPn. Use the
| FPCR_MODE byte to get rounding on norms and zeros.
|
cu_nmnr:
bfextu FPCR_MODE(%a6){#0:#2},%d0
tstb %d0 |check for extended
beq cu_wrexn |if so, just write result
cmpib #1,%d0 |check for single
beq cu_nmrs |fall through to double
|
| The move is fdmove or round precision is double.
|
cu_nmrd:
movel #2,%d0 |set up the size for denorm
movew LOCAL_EX(%a0),%d1 |compare exponent to double threshold
andw #0x7fff,%d1
cmpw #0x3c01,%d1
bls cu_nunfl
bfextu FPCR_MODE(%a6){#2:#2},%d1 |get rmode
orl #0x00020000,%d1 |or in rprec (double)
clrl %d0 |clear g,r,s for round
bclrb #sign_bit,LOCAL_EX(%a0) |convert to internal format
sne LOCAL_SGN(%a0)
bsrl round
bfclr LOCAL_SGN(%a0){#0:#8}
beqs cu_nmrdc
bsetb #sign_bit,LOCAL_EX(%a0)
cu_nmrdc:
movew LOCAL_EX(%a0),%d1 |check for overflow
andw #0x7fff,%d1
cmpw #0x43ff,%d1
bge cu_novfl |take care of overflow case
bra cu_wrexn
|
| The move is fsmove or round precision is single.
|
cu_nmrs:
movel #1,%d0
movew LOCAL_EX(%a0),%d1
andw #0x7fff,%d1
cmpw #0x3f81,%d1
bls cu_nunfl
bfextu FPCR_MODE(%a6){#2:#2},%d1
orl #0x00010000,%d1
clrl %d0
bclrb #sign_bit,LOCAL_EX(%a0)
sne LOCAL_SGN(%a0)
bsrl round
bfclr LOCAL_SGN(%a0){#0:#8}
beqs cu_nmrsc
bsetb #sign_bit,LOCAL_EX(%a0)
cu_nmrsc:
movew LOCAL_EX(%a0),%d1
andw #0x7FFF,%d1
cmpw #0x407f,%d1
blt cu_wrexn
|
| The operand is above precision boundaries. Use t_ovfl to
| generate the correct value.
|
cu_novfl:
bsr t_ovfl
bra cu_wrexn
|
| The operand is below precision boundaries. Use denorm to
| generate the correct value.
|
cu_nunfl:
bclrb #sign_bit,LOCAL_EX(%a0)
sne LOCAL_SGN(%a0)
bsr denorm
bfclr LOCAL_SGN(%a0){#0:#8} |change back to IEEE ext format
beqs cu_nucont
bsetb #sign_bit,LOCAL_EX(%a0)
cu_nucont:
bfextu FPCR_MODE(%a6){#2:#2},%d1
btstb #2,CMDREG1B+1(%a6) |check for rd
bne inst_d
btstb #6,CMDREG1B+1(%a6) |check for rs
bne inst_s
swap %d1
moveb FPCR_MODE(%a6),%d1
lsrb #6,%d1
swap %d1
bra inst_sd
inst_d:
orl #0x00020000,%d1
bra inst_sd
inst_s:
orl #0x00010000,%d1
inst_sd:
bclrb #sign_bit,LOCAL_EX(%a0)
sne LOCAL_SGN(%a0)
bsrl round
bfclr LOCAL_SGN(%a0){#0:#8}
beqs cu_nuflp
bsetb #sign_bit,LOCAL_EX(%a0)
cu_nuflp:
btstb #inex2_bit,FPSR_EXCEPT(%a6)
beqs cu_nuninx
orl #aunfl_mask,USER_FPSR(%a6) |if the round was inex, set AUNFL
cu_nuninx:
tstl LOCAL_HI(%a0) |test for zero
bnes cu_nunzro
tstl LOCAL_LO(%a0)
bnes cu_nunzro
|
| The mantissa is zero from the denorm loop. Check sign and rmode
| to see if rounding should have occurred which would leave the lsb.
|
movel USER_FPCR(%a6),%d0
andil #0x30,%d0 |isolate rmode
cmpil #0x20,%d0
blts cu_nzro
bnes cu_nrp
cu_nrm:
tstw LOCAL_EX(%a0) |if positive, set lsb
bges cu_nzro
btstb #7,FPCR_MODE(%a6) |check for double
beqs cu_nincs
bras cu_nincd
cu_nrp:
tstw LOCAL_EX(%a0) |if positive, set lsb
blts cu_nzro
btstb #7,FPCR_MODE(%a6) |check for double
beqs cu_nincs
cu_nincd:
orl #0x800,LOCAL_LO(%a0) |inc for double
bra cu_nunzro
cu_nincs:
orl #0x100,LOCAL_HI(%a0) |inc for single
bra cu_nunzro
cu_nzro:
orl #z_mask,USER_FPSR(%a6)
moveb STAG(%a6),%d0
andib #0xe0,%d0
cmpib #0x40,%d0 |check if input was tagged zero
beqs cu_numv
cu_nunzro:
orl #unfl_mask,USER_FPSR(%a6) |set unfl
cu_numv:
movel (%a0),ETEMP(%a6)
movel 4(%a0),ETEMP_HI(%a6)
movel 8(%a0),ETEMP_LO(%a6)
|
| Write the result to memory, setting the fpsr cc bits. NaN and Inf
| bypass cu_wrexn.
|
cu_wrexn:
tstw LOCAL_EX(%a0) |test for zero
beqs cu_wrzero
cmpw #0x8000,LOCAL_EX(%a0) |test for zero
bnes cu_wreon
cu_wrzero:
orl #z_mask,USER_FPSR(%a6) |set Z bit
cu_wreon:
tstw LOCAL_EX(%a0)
bpl wr_etemp
orl #neg_mask,USER_FPSR(%a6)
bra wr_etemp
|
| HANDLE SOURCE DENORM HERE
|
| ;clear denorm stag to norm
| ;write the new tag & ete15 to the fstack
mon_dnrm:
|
| At this point, check for the cases in which normalizing the
| denorm produces incorrect results.
|
tstb DY_MO_FLG(%a6) |all cases of dyadic instructions would
bnes nrm_src |require normalization of denorm
| At this point:
| monadic instructions: fabs = $18 fneg = $1a ftst = $3a
| fmove = $00 fsmove = $40 fdmove = $44
| fsqrt = $05* fssqrt = $41 fdsqrt = $45
| (*fsqrt reencoded to $05)
|
movew CMDREG1B(%a6),%d0 |get command register
andil #0x7f,%d0 |strip to only command word
|
| At this point, fabs, fneg, fsmove, fdmove, ftst, fsqrt, fssqrt, and
| fdsqrt are possible.
| For cases fabs, fneg, fsmove, and fdmove goto spos (do not normalize)
| For cases fsqrt, fssqrt, and fdsqrt goto nrm_src (do normalize)
|
btstl #0,%d0
bnes nrm_src |weed out fsqrt instructions
st CU_ONLY(%a6) |set cu-only inst flag
bra cu_dnrm |fmove, fabs, fneg, ftst
| ;cases go to cu_dnrm
nrm_src:
bclrb #sign_bit,LOCAL_EX(%a0)
sne LOCAL_SGN(%a0)
bsr nrm_set |normalize number (exponent will go
| ; negative)
bclrb #sign_bit,LOCAL_EX(%a0) |get rid of false sign
bfclr LOCAL_SGN(%a0){#0:#8} |change back to IEEE ext format
beqs spos
bsetb #sign_bit,LOCAL_EX(%a0)
spos:
bfclr STAG(%a6){#0:#4} |set tag to normalized, FPTE15 = 0
bsetb #4,STAG(%a6) |set ETE15
orb #0xf0,DNRM_FLG(%a6)
normal:
tstb DNRM_FLG(%a6) |check if any of the ops were denorms
bne ck_wrap |if so, check if it is a potential
| ;wrap-around case
fix_stk:
moveb #0xfe,CU_SAVEPC(%a6)
bclrb #E1,E_BYTE(%a6)
clrw NMNEXC(%a6)
st RES_FLG(%a6) |indicate that a restore is needed
rts
|
| cu_dnrm handles all cu-only instructions (fmove, fabs, fneg, and
| ftst) completely in software without an frestore to the 040.
|
cu_dnrm:
st CU_ONLY(%a6)
movew CMDREG1B(%a6),%d0
andib #0x3b,%d0 |isolate bits to select inst
tstb %d0
beql cu_dmove |if zero, it is an fmove
cmpib #0x18,%d0
beql cu_dabs |if $18, it is fabs
cmpib #0x1a,%d0
beql cu_dneg |if $1a, it is fneg
|
| Inst is ftst. Check the source operand and set the cc's accordingly.
| No write is done, so simply rts.
|
cu_dtst:
movew LOCAL_EX(%a0),%d0
bclrl #15,%d0
sne LOCAL_SGN(%a0)
beqs cu_dtpo
orl #neg_mask,USER_FPSR(%a6) |set N
cu_dtpo:
cmpiw #0x7fff,%d0 |test for inf/nan
bnes cu_dtcz
tstl LOCAL_HI(%a0)
bnes cu_dtn
tstl LOCAL_LO(%a0)
bnes cu_dtn
orl #inf_mask,USER_FPSR(%a6)
rts
cu_dtn:
orl #nan_mask,USER_FPSR(%a6)
movel ETEMP_EX(%a6),FPTEMP_EX(%a6) |set up fptemp sign for
| ;snan handler
rts
cu_dtcz:
tstl LOCAL_HI(%a0)
bnel cu_dtsx
tstl LOCAL_LO(%a0)
bnel cu_dtsx
orl #z_mask,USER_FPSR(%a6)
cu_dtsx:
rts
|
| Inst is fabs. Execute the absolute value function on the input.
| Branch to the fmove code.
|
cu_dabs:
bclrb #7,LOCAL_EX(%a0) |do abs
bras cu_dmove |fmove code will finish
|
| Inst is fneg. Execute the negate value function on the input.
| Fall though to the fmove code.
|
cu_dneg:
bchgb #7,LOCAL_EX(%a0) |do neg
|
| Inst is fmove. This code also handles all result writes.
| If bit 2 is set, round is forced to double. If it is clear,
| and bit 6 is set, round is forced to single. If both are clear,
| the round precision is found in the fpcr. If the rounding precision
| is double or single, the result is zero, and the mode is checked
| to determine if the lsb of the result should be set.
|
cu_dmove:
btstb #2,CMDREG1B+1(%a6) |check for rd
bne cu_dmrd
btstb #6,CMDREG1B+1(%a6) |check for rs
bne cu_dmrs
|
| The move or operation is not with forced precision. Use the
| FPCR_MODE byte to get rounding.
|
cu_dmnr:
bfextu FPCR_MODE(%a6){#0:#2},%d0
tstb %d0 |check for extended
beq cu_wrexd |if so, just write result
cmpib #1,%d0 |check for single
beq cu_dmrs |fall through to double
|
| The move is fdmove or round precision is double. Result is zero.
| Check rmode for rp or rm and set lsb accordingly.
|
cu_dmrd:
bfextu FPCR_MODE(%a6){#2:#2},%d1 |get rmode
tstw LOCAL_EX(%a0) |check sign
blts cu_dmdn
cmpib #3,%d1 |check for rp
bne cu_dpd |load double pos zero
bra cu_dpdr |load double pos zero w/lsb
cu_dmdn:
cmpib #2,%d1 |check for rm
bne cu_dnd |load double neg zero
bra cu_dndr |load double neg zero w/lsb
|
| The move is fsmove or round precision is single. Result is zero.
| Check for rp or rm and set lsb accordingly.
|
cu_dmrs:
bfextu FPCR_MODE(%a6){#2:#2},%d1 |get rmode
tstw LOCAL_EX(%a0) |check sign
blts cu_dmsn
cmpib #3,%d1 |check for rp
bne cu_spd |load single pos zero
bra cu_spdr |load single pos zero w/lsb
cu_dmsn:
cmpib #2,%d1 |check for rm
bne cu_snd |load single neg zero
bra cu_sndr |load single neg zero w/lsb
|
| The precision is extended, so the result in etemp is correct.
| Simply set unfl (not inex2 or aunfl) and write the result to
| the correct fp register.
cu_wrexd:
orl #unfl_mask,USER_FPSR(%a6)
tstw LOCAL_EX(%a0)
beq wr_etemp
orl #neg_mask,USER_FPSR(%a6)
bra wr_etemp
|
| These routines write +/- zero in double format. The routines
| cu_dpdr and cu_dndr set the double lsb.
|
cu_dpd:
movel #0x3c010000,LOCAL_EX(%a0) |force pos double zero
clrl LOCAL_HI(%a0)
clrl LOCAL_LO(%a0)
orl #z_mask,USER_FPSR(%a6)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
cu_dpdr:
movel #0x3c010000,LOCAL_EX(%a0) |force pos double zero
clrl LOCAL_HI(%a0)
movel #0x800,LOCAL_LO(%a0) |with lsb set
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
cu_dnd:
movel #0xbc010000,LOCAL_EX(%a0) |force pos double zero
clrl LOCAL_HI(%a0)
clrl LOCAL_LO(%a0)
orl #z_mask,USER_FPSR(%a6)
orl #neg_mask,USER_FPSR(%a6)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
cu_dndr:
movel #0xbc010000,LOCAL_EX(%a0) |force pos double zero
clrl LOCAL_HI(%a0)
movel #0x800,LOCAL_LO(%a0) |with lsb set
orl #neg_mask,USER_FPSR(%a6)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
|
| These routines write +/- zero in single format. The routines
| cu_dpdr and cu_dndr set the single lsb.
|
cu_spd:
movel #0x3f810000,LOCAL_EX(%a0) |force pos single zero
clrl LOCAL_HI(%a0)
clrl LOCAL_LO(%a0)
orl #z_mask,USER_FPSR(%a6)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
cu_spdr:
movel #0x3f810000,LOCAL_EX(%a0) |force pos single zero
movel #0x100,LOCAL_HI(%a0) |with lsb set
clrl LOCAL_LO(%a0)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
cu_snd:
movel #0xbf810000,LOCAL_EX(%a0) |force pos single zero
clrl LOCAL_HI(%a0)
clrl LOCAL_LO(%a0)
orl #z_mask,USER_FPSR(%a6)
orl #neg_mask,USER_FPSR(%a6)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
cu_sndr:
movel #0xbf810000,LOCAL_EX(%a0) |force pos single zero
movel #0x100,LOCAL_HI(%a0) |with lsb set
clrl LOCAL_LO(%a0)
orl #neg_mask,USER_FPSR(%a6)
orl #unfinx_mask,USER_FPSR(%a6)
bra wr_etemp
|
| This code checks for 16-bit overflow conditions on dyadic
| operations which are not restorable into the floating-point
| unit and must be completed in software. Basically, this
| condition exists with a very large norm and a denorm. One
| of the operands must be denormalized to enter this code.
|
| Flags used:
| DY_MO_FLG contains 0 for monadic op, $ff for dyadic
| DNRM_FLG contains $00 for neither op denormalized
| $0f for the destination op denormalized
| $f0 for the source op denormalized
| $ff for both ops denormalized
|
| The wrap-around condition occurs for add, sub, div, and cmp
| when
|
| abs(dest_exp - src_exp) >= $8000
|
| and for mul when
|
| (dest_exp + src_exp) < $0
|
| we must process the operation here if this case is true.
|
| The rts following the frcfpn routine is the exit from res_func
| for this condition. The restore flag (RES_FLG) is left clear.
| No frestore is done unless an exception is to be reported.
|
| For fadd:
| if(sign_of(dest) != sign_of(src))
| replace exponent of src with $3fff (keep sign)
| use fpu to perform dest+new_src (user's rmode and X)
| clr sticky
| else
| set sticky
| call round with user's precision and mode
| move result to fpn and wbtemp
|
| For fsub:
| if(sign_of(dest) == sign_of(src))
| replace exponent of src with $3fff (keep sign)
| use fpu to perform dest+new_src (user's rmode and X)
| clr sticky
| else
| set sticky
| call round with user's precision and mode
| move result to fpn and wbtemp
|
| For fdiv/fsgldiv:
| if(both operands are denorm)
| restore_to_fpu;
| if(dest is norm)
| force_ovf;
| else(dest is denorm)
| force_unf:
|
| For fcmp:
| if(dest is norm)
| N = sign_of(dest);
| else(dest is denorm)
| N = sign_of(src);
|
| For fmul:
| if(both operands are denorm)
| force_unf;
| if((dest_exp + src_exp) < 0)
| force_unf:
| else
| restore_to_fpu;
|
| local equates:
.set addcode,0x22
.set subcode,0x28
.set mulcode,0x23
.set divcode,0x20
.set cmpcode,0x38
ck_wrap:
| tstb DY_MO_FLG(%a6) ;check for fsqrt
beq fix_stk |if zero, it is fsqrt
movew CMDREG1B(%a6),%d0
andiw #0x3b,%d0 |strip to command bits
cmpiw #addcode,%d0
beq wrap_add
cmpiw #subcode,%d0
beq wrap_sub
cmpiw #mulcode,%d0
beq wrap_mul
cmpiw #cmpcode,%d0
beq wrap_cmp
|
| Inst is fdiv.
|
wrap_div:
cmpb #0xff,DNRM_FLG(%a6) |if both ops denorm,
beq fix_stk |restore to fpu
|
| One of the ops is denormalized. Test for wrap condition
| and force the result.
|
cmpb #0x0f,DNRM_FLG(%a6) |check for dest denorm
bnes div_srcd
div_destd:
bsrl ckinf_ns
bne fix_stk
bfextu ETEMP_EX(%a6){#1:#15},%d0 |get src exp (always pos)
bfexts FPTEMP_EX(%a6){#1:#15},%d1 |get dest exp (always neg)
subl %d1,%d0 |subtract dest from src
cmpl #0x7fff,%d0
blt fix_stk |if less, not wrap case
clrb WBTEMP_SGN(%a6)
movew ETEMP_EX(%a6),%d0 |find the sign of the result
movew FPTEMP_EX(%a6),%d1
eorw %d1,%d0
andiw #0x8000,%d0
beq force_unf
st WBTEMP_SGN(%a6)
bra force_unf
ckinf_ns:
moveb STAG(%a6),%d0 |check source tag for inf or nan
bra ck_in_com
ckinf_nd:
moveb DTAG(%a6),%d0 |check destination tag for inf or nan
ck_in_com:
andib #0x60,%d0 |isolate tag bits
cmpb #0x40,%d0 |is it inf?
beq nan_or_inf |not wrap case
cmpb #0x60,%d0 |is it nan?
beq nan_or_inf |yes, not wrap case?
cmpb #0x20,%d0 |is it a zero?
beq nan_or_inf |yes
clrl %d0
rts |then ; it is either a zero of norm,
| ;check wrap case
nan_or_inf:
moveql #-1,%d0
rts
div_srcd:
bsrl ckinf_nd
bne fix_stk
bfextu FPTEMP_EX(%a6){#1:#15},%d0 |get dest exp (always pos)
bfexts ETEMP_EX(%a6){#1:#15},%d1 |get src exp (always neg)
subl %d1,%d0 |subtract src from dest
cmpl #0x8000,%d0
blt fix_stk |if less, not wrap case
clrb WBTEMP_SGN(%a6)
movew ETEMP_EX(%a6),%d0 |find the sign of the result
movew FPTEMP_EX(%a6),%d1
eorw %d1,%d0
andiw #0x8000,%d0
beqs force_ovf
st WBTEMP_SGN(%a6)
|
| This code handles the case of the instruction resulting in
| an overflow condition.
|
force_ovf:
bclrb #E1,E_BYTE(%a6)
orl #ovfl_inx_mask,USER_FPSR(%a6)
clrw NMNEXC(%a6)
leal WBTEMP(%a6),%a0 |point a0 to memory location
movew CMDREG1B(%a6),%d0
btstl #6,%d0 |test for forced precision
beqs frcovf_fpcr
btstl #2,%d0 |check for double
bnes frcovf_dbl
movel #0x1,%d0 |inst is forced single
bras frcovf_rnd
frcovf_dbl:
movel #0x2,%d0 |inst is forced double
bras frcovf_rnd
frcovf_fpcr:
bfextu FPCR_MODE(%a6){#0:#2},%d0 |inst not forced - use fpcr prec
frcovf_rnd:
| The 881/882 does not set inex2 for the following case, so the
| line is commented out to be compatible with 881/882
| tst.b %d0
| beq.b frcovf_x
| or.l #inex2_mask,USER_FPSR(%a6) ;if prec is s or d, set inex2
|frcovf_x:
bsrl ovf_res |get correct result based on
| ;round precision/mode. This
| ;sets FPSR_CC correctly
| ;returns in external format
bfclr WBTEMP_SGN(%a6){#0:#8}
beq frcfpn
bsetb #sign_bit,WBTEMP_EX(%a6)
bra frcfpn
|
| Inst is fadd.
|
wrap_add:
cmpb #0xff,DNRM_FLG(%a6) |if both ops denorm,
beq fix_stk |restore to fpu
|
| One of the ops is denormalized. Test for wrap condition
| and complete the instruction.
|
cmpb #0x0f,DNRM_FLG(%a6) |check for dest denorm
bnes add_srcd
add_destd:
bsrl ckinf_ns
bne fix_stk
bfextu ETEMP_EX(%a6){#1:#15},%d0 |get src exp (always pos)
bfexts FPTEMP_EX(%a6){#1:#15},%d1 |get dest exp (always neg)
subl %d1,%d0 |subtract dest from src
cmpl #0x8000,%d0
blt fix_stk |if less, not wrap case
bra add_wrap
add_srcd:
bsrl ckinf_nd
bne fix_stk
bfextu FPTEMP_EX(%a6){#1:#15},%d0 |get dest exp (always pos)
bfexts ETEMP_EX(%a6){#1:#15},%d1 |get src exp (always neg)
subl %d1,%d0 |subtract src from dest
cmpl #0x8000,%d0
blt fix_stk |if less, not wrap case
|
| Check the signs of the operands. If they are unlike, the fpu
| can be used to add the norm and 1.0 with the sign of the
| denorm and it will correctly generate the result in extended
| precision. We can then call round with no sticky and the result
| will be correct for the user's rounding mode and precision. If
| the signs are the same, we call round with the sticky bit set
| and the result will be correct for the user's rounding mode and
| precision.
|
add_wrap:
movew ETEMP_EX(%a6),%d0
movew FPTEMP_EX(%a6),%d1
eorw %d1,%d0
andiw #0x8000,%d0
beq add_same
|
| The signs are unlike.
|
cmpb #0x0f,DNRM_FLG(%a6) |is dest the denorm?
bnes add_u_srcd
movew FPTEMP_EX(%a6),%d0
andiw #0x8000,%d0
orw #0x3fff,%d0 |force the exponent to +/- 1
movew %d0,FPTEMP_EX(%a6) |in the denorm
movel USER_FPCR(%a6),%d0
andil #0x30,%d0
fmovel %d0,%fpcr |set up users rmode and X
fmovex ETEMP(%a6),%fp0
faddx FPTEMP(%a6),%fp0
leal WBTEMP(%a6),%a0 |point a0 to wbtemp in frame
fmovel %fpsr,%d1
orl %d1,USER_FPSR(%a6) |capture cc's and inex from fadd
fmovex %fp0,WBTEMP(%a6) |write result to memory
lsrl #4,%d0 |put rmode in lower 2 bits
movel USER_FPCR(%a6),%d1
andil #0xc0,%d1
lsrl #6,%d1 |put precision in upper word
swap %d1
orl %d0,%d1 |set up for round call
clrl %d0 |force sticky to zero
bclrb #sign_bit,WBTEMP_EX(%a6)
sne WBTEMP_SGN(%a6)
bsrl round |round result to users rmode & prec
bfclr WBTEMP_SGN(%a6){#0:#8} |convert back to IEEE ext format
beq frcfpnr
bsetb #sign_bit,WBTEMP_EX(%a6)
bra frcfpnr
add_u_srcd:
movew ETEMP_EX(%a6),%d0
andiw #0x8000,%d0
orw #0x3fff,%d0 |force the exponent to +/- 1
movew %d0,ETEMP_EX(%a6) |in the denorm
movel USER_FPCR(%a6),%d0
andil #0x30,%d0
fmovel %d0,%fpcr |set up users rmode and X
fmovex ETEMP(%a6),%fp0
faddx FPTEMP(%a6),%fp0
fmovel %fpsr,%d1
orl %d1,USER_FPSR(%a6) |capture cc's and inex from fadd
leal WBTEMP(%a6),%a0 |point a0 to wbtemp in frame
fmovex %fp0,WBTEMP(%a6) |write result to memory
lsrl #4,%d0 |put rmode in lower 2 bits
movel USER_FPCR(%a6),%d1
andil #0xc0,%d1
lsrl #6,%d1 |put precision in upper word
swap %d1
orl %d0,%d1 |set up for round call
clrl %d0 |force sticky to zero
bclrb #sign_bit,WBTEMP_EX(%a6)
sne WBTEMP_SGN(%a6) |use internal format for round
bsrl round |round result to users rmode & prec
bfclr WBTEMP_SGN(%a6){#0:#8} |convert back to IEEE ext format
beq frcfpnr
bsetb #sign_bit,WBTEMP_EX(%a6)
bra frcfpnr
|
| Signs are alike:
|
add_same:
cmpb #0x0f,DNRM_FLG(%a6) |is dest the denorm?
bnes add_s_srcd
add_s_destd:
leal ETEMP(%a6),%a0
movel USER_FPCR(%a6),%d0
andil #0x30,%d0
lsrl #4,%d0 |put rmode in lower 2 bits
movel USER_FPCR(%a6),%d1
andil #0xc0,%d1
lsrl #6,%d1 |put precision in upper word
swap %d1
orl %d0,%d1 |set up for round call
movel #0x20000000,%d0 |set sticky for round
bclrb #sign_bit,ETEMP_EX(%a6)
sne ETEMP_SGN(%a6)
bsrl round |round result to users rmode & prec
bfclr ETEMP_SGN(%a6){#0:#8} |convert back to IEEE ext format
beqs add_s_dclr
bsetb #sign_bit,ETEMP_EX(%a6)
add_s_dclr:
leal WBTEMP(%a6),%a0
movel ETEMP(%a6),(%a0) |write result to wbtemp
movel ETEMP_HI(%a6),4(%a0)
movel ETEMP_LO(%a6),8(%a0)
tstw ETEMP_EX(%a6)
bgt add_ckovf
orl #neg_mask,USER_FPSR(%a6)
bra add_ckovf
add_s_srcd:
leal FPTEMP(%a6),%a0
movel USER_FPCR(%a6),%d0
andil #0x30,%d0
lsrl #4,%d0 |put rmode in lower 2 bits
movel USER_FPCR(%a6),%d1
andil #0xc0,%d1
lsrl #6,%d1 |put precision in upper word
swap %d1
orl %d0,%d1 |set up for round call
movel #0x20000000,%d0 |set sticky for round
bclrb #sign_bit,FPTEMP_EX(%a6)
sne FPTEMP_SGN(%a6)
bsrl round |round result to users rmode & prec
bfclr FPTEMP_SGN(%a6){#0:#8} |convert back to IEEE ext format
beqs add_s_sclr
bsetb #sign_bit,FPTEMP_EX(%a6)
add_s_sclr:
leal WBTEMP(%a6),%a0
movel FPTEMP(%a6),(%a0) |write result to wbtemp
movel FPTEMP_HI(%a6),4(%a0)
movel FPTEMP_LO(%a6),8(%a0)
tstw FPTEMP_EX(%a6)
bgt add_ckovf
orl #neg_mask,USER_FPSR(%a6)
add_ckovf:
movew WBTEMP_EX(%a6),%d0
andiw #0x7fff,%d0
cmpiw #0x7fff,%d0
bne frcfpnr
|
| The result has overflowed to $7fff exponent. Set I, ovfl,
| and aovfl, and clr the mantissa (incorrectly set by the
| round routine.)
|
orl #inf_mask+ovfl_inx_mask,USER_FPSR(%a6)
clrl 4(%a0)
bra frcfpnr
|
| Inst is fsub.
|
wrap_sub:
cmpb #0xff,DNRM_FLG(%a6) |if both ops denorm,
beq fix_stk |restore to fpu
|
| One of the ops is denormalized. Test for wrap condition
| and complete the instruction.
|
cmpb #0x0f,DNRM_FLG(%a6) |check for dest denorm
bnes sub_srcd
sub_destd:
bsrl ckinf_ns
bne fix_stk
bfextu ETEMP_EX(%a6){#1:#15},%d0 |get src exp (always pos)
bfexts FPTEMP_EX(%a6){#1:#15},%d1 |get dest exp (always neg)
subl %d1,%d0 |subtract src from dest
cmpl #0x8000,%d0
blt fix_stk |if less, not wrap case
bra sub_wrap
sub_srcd:
bsrl ckinf_nd
bne fix_stk
bfextu FPTEMP_EX(%a6){#1:#15},%d0 |get dest exp (always pos)
bfexts ETEMP_EX(%a6){#1:#15},%d1 |get src exp (always neg)
subl %d1,%d0 |subtract dest from src
cmpl #0x8000,%d0
blt fix_stk |if less, not wrap case
|
| Check the signs of the operands. If they are alike, the fpu
| can be used to subtract from the norm 1.0 with the sign of the