ack/mach/m65oo2/libem/fp8087.s

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2024-02-22 15:13:52 +00:00
.define .adf4, .adf8, .sbf4, .sbf8, .mlf4, .mlf8, .dvf4, .dvf8
.define .ngf4, .ngf8, .fif4, .fif8, .fef4, .fef8
.define .cif4, .cif8, .cuf4, .cuf8, .cfi, .cfu, .cff4, .cff8
.define .cmf4, .cmf8
.sect .text; .sect .rom; .sect .data; .sect .bss
! $Id$
! Implement interface to floating point package for Intel 8087
.sect .rom
one:
.data2 1
two:
.data2 2
bigmin:
.data2 0, -32768
.sect .text
.adf4:
mov bx,sp
wait
flds 2(bx)
wait
fadds 6(bx)
wait
fstps 6(bx)
wait
ret
.adf8:
mov bx,sp
wait
fldd 2(bx)
wait
faddd 10(bx)
wait
fstpd 10(bx)
wait
ret
.sbf4:
mov bx,sp
wait
flds 6(bx)
wait
fsubs 2(bx)
wait
fstps 6(bx)
wait
ret
.sbf8:
mov bx,sp
wait
fldd 10(bx)
wait
fsubd 2(bx)
wait
fstpd 10(bx)
wait
ret
.mlf4:
mov bx,sp
wait
flds 2(bx)
wait
fmuls 6(bx)
wait
fstps 6(bx)
wait
ret
.mlf8:
mov bx,sp
wait
fldd 2(bx)
wait
fmuld 10(bx)
wait
fstpd 10(bx)
wait
ret
.dvf4:
mov bx,sp
wait
flds 6(bx)
wait
fdivs 2(bx)
wait
fstps 6(bx)
wait
ret
.dvf8:
mov bx,sp
wait
fldd 10(bx)
wait
fdivd 2(bx)
wait
fstpd 10(bx)
wait
ret
.ngf4:
mov bx,sp
wait
flds 2(bx)
wait
fchs
wait
fstps 2(bx)
wait
ret
.ngf8:
mov bx,sp
wait
fldd 2(bx)
wait
fchs
wait
fstpd 2(bx)
wait
ret
.fif4:
mov bx,sp
push bx ! make room for FP status word
wait
flds 4(bx)
wait
fmuls 8(bx) ! multiply
wait
fld st ! copy result
wait
ftst ! test sign; handle negative separately
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf ! result of test in condition codes
jb 1f
frndint ! this one rounds (?)
wait
fcom st(1) ! compare with original; if <=, then OK
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf
jbe 2f
fisubs (one) ! else subtract 1
wait
jmp 2f
1: ! here, negative case
frndint ! this one rounds (?)
wait
fcom st(1) ! compare with original; if >=, then OK
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf
jae 2f
fiadds (one) ! else add 1
wait
2:
fsub st(1),st ! subtract integer part
wait
mov bx,2(bx)
fstps (bx)
wait
fstps 4(bx)
wait
pop bx
ret
.fif8:
mov bx,sp
push bx ! make room for FP status word
wait
fldd 4(bx)
wait
fmuld 12(bx) ! multiply
wait
fld st ! and copy result
wait
ftst ! test sign; handle negative separately
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf ! result of test in condition codes
jb 1f
frndint ! this one rounds (?)
wait
fcom st(1) ! compare with original; if <=, then OK
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf
jbe 2f
fisubs (one) ! else subtract 1
wait
jmp 2f
1: ! here, negative case
frndint ! this one rounds (?)
wait
fcom st(1) ! compare with original; if >=, then OK
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf
jae 2f
fiadds (one) ! else add 1
wait
2:
fsub st(1),st ! subtract integer part
mov bx,2(bx)
fstpd (bx)
wait
fstpd 8(bx)
wait
pop bx
ret
.fef4:
! this could be simpler, if only the
! fxtract instruction was emulated properly
mov bx,sp
mov ax,6(bx)
and ax,077600
je 1f ! zero exponent
mov cx,7
shr ax,cl
sub ax,126
mov cx,ax ! exponent in cx
mov ax,6(bx)
and ax,0100177
or ax,0037400 ! load -1 exponent
mov dx,4(bx)
mov bx,2(bx)
mov 4(bx),ax
mov 2(bx),dx
mov (bx),cx
ret
1: ! we get here on zero exp
mov ax,6(bx)
and ax,0177
or ax,4(bx)
jne 1f ! zero result
xor ax,ax
mov bx,2(bx)
mov (bx),ax
mov 2(bx),ax
mov 4(bx),ax
ret
1: ! otherwise unnormalized number
mov cx,6(bx)
and cx,0100177
mov dx,cx
and cx,0x8000
mov ax,-125
2:
test dx,0x80
jne 1f
dec ax
shl 4(bx),1
rcl dx,1
or dx,cx
jmp 2b
1:
mov cx,4(bx)
mov bx,2(bx)
mov (bx),ax
mov 2(bx),cx
and dx,0100177
or dx,0037400 ! load -1 exponent
mov 4(bx),dx
ret
.fef8:
! this could be simpler, if only the
! fxtract instruction was emulated properly
mov bx,sp
mov ax,10(bx)
and ax,077760
je 1f ! zero exponent
mov cx,4
shr ax,cl
sub ax,1022
mov cx,ax ! exponent in cx
mov ax,10(bx)
and ax,0100017
or ax,0037740 ! load -1 exponent
push 8(bx)
push 6(bx)
push 4(bx)
mov bx,2(bx)
pop 2(bx)
pop 4(bx)
pop 6(bx)
mov 8(bx),ax
mov (bx),cx
ret
1: ! we get here on zero exp
mov ax,10(bx)
and ax,017
or ax,8(bx)
or ax,6(bx)
or ax,4(bx)
jne 1f ! zero result
xor ax,ax
mov bx,2(bx)
mov (bx),ax
mov 2(bx),ax
mov 4(bx),ax
mov 6(bx),ax
mov 8(bx),ax
ret
1: ! otherwise unnormalized number
mov cx,10(bx)
and cx,0100017
mov dx,cx
and cx,0x8000
mov ax,-1021
2:
test dx,0x10
jne 1f
dec ax
shl 4(bx),1
rcl 6(bx),1
rcl 8(bx),1
rcl dx,1
or dx,cx
jmp 2b
1:
and dx,0100017
or dx,0037740 ! load -1 exponent
mov cx,8(bx)
push 6(bx)
push 4(bx)
mov bx,2(bx)
mov (bx),ax
mov 8(bx),dx
mov 6(bx),cx
pop 2(bx)
pop 4(bx)
ret
.cif4:
mov bx,sp
cmp 2(bx),2
jne 1f
wait
filds 4(bx)
wait
fstps 2(bx)
wait
ret
1:
wait
fildl 4(bx)
wait
fstps 4(bx)
wait
ret
.cif8:
mov bx,sp
cmp 2(bx),2
jne 1f
wait
filds 4(bx)
wait
fstpd 2(bx)
wait
ret
1:
wait
fildl 4(bx)
wait
fstpd 2(bx)
wait
ret
.cuf4:
mov bx,sp
cmp 2(bx),2
jne 1f
mov ax,4(bx)
mov 2(bx),ax
mov 4(bx),0
wait
fildl 2(bx)
wait
fstps 2(bx)
wait
ret
1:
wait
fildl 4(bx)
wait
cmp 6(bx),0
jge 1f
2:
wait
fisubl (bigmin)
wait
fisubl (bigmin)
1:
wait
fstps 4(bx)
wait
ret
.cuf8:
mov bx,sp
cmp 2(bx),2
jne 1f
mov 6(bx),0
1:
wait
fildl 4(bx)
wait
cmp 6(bx),0
jge 1f
2:
wait
fisubl (bigmin)
wait
fisubl (bigmin)
1:
wait
fstpd 2(bx)
wait
ret
.cfi:
mov bx,sp
push bx
wait
fstcw -2(bx)
wait
mov dx,-2(bx)
or -2(bx),0xc00 ! truncating mode
wait
fldcw -2(bx)
pop ax
cmp 4(bx),4
jne 2f
! loc 4 loc ? cfi
wait
flds 6(bx)
wait
fistpl 6(bx)
wait
cmp 2(bx),2
jne 1f
mov ax,6(bx)
1:
mov 4(bx),dx
wait
fldcw 4(bx)
wait
ret
2:
! loc 8 loc ? cfi
wait
fldd 6(bx)
wait
fistpl 10(bx)
wait
cmp 2(bx),2
jne 1b
mov ax,10(bx)
jmp 1b
.cfu:
mov bx,sp
push bx
wait
fstcw -2(bx)
wait
mov dx,-2(bx)
and -2(bx),0xf3ff
or -2(bx),0x400 ! to -infinity
wait
fldcw -2(bx)
wait
pop ax
cmp 4(bx),4
jne 2f
! loc 4 loc ? cfu
flds 6(bx)
wait
fabs ! ???
wait
fiaddl (bigmin)
fistpl 6(bx)
wait
mov ax,8(bx)
sub ax,(bigmin+2)
mov 8(bx),ax
cmp 2(bx),2
jne 1f
mov ax,6(bx)
1:
mov 4(bx),dx
wait
fldcw 4(bx)
wait
ret
2:
wait
! loc 8 loc ? cfu
fldd 6(bx)
wait
fabs ! ???
wait
fiaddl (bigmin)
fistpl 10(bx)
wait
mov ax,12(bx)
sub ax,(bigmin+2)
mov 12(bx),ax
cmp 2(bx),2
jne 1b
mov ax,10(bx)
jmp 1b
.cff4:
mov bx,sp
wait
fldd 2(bx)
wait
fstcw 2(bx)
wait
mov dx,2(bx)
and 2(bx),0xf3ff ! set to rounding mode
wait
fldcw 2(bx)
wait
fstps 6(bx)
mov 2(bx),dx
wait
fldcw 2(bx)
wait
ret
.cff8:
mov bx,sp
wait
flds 2(bx)
wait
fstpd 2(bx)
wait
ret
.cmf4:
mov bx,sp
push bx ! room for 8087 status word
xor cx,cx
wait
flds 6(bx)
wait
flds 2(bx)
wait
fcompp ! compare and pop operands
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf
je 1f
jb 2f
dec cx
jmp 1f
2:
inc cx
1:
mov ax,cx
pop bx
ret
.cmf8:
mov bx,sp
push bx ! room for 8087 status word
xor cx,cx
wait
fldd 10(bx)
wait
fldd 2(bx)
wait
fcompp ! compare and pop operands
wait
fstsw -2(bx)
wait
mov ax,-2(bx)
sahf
je 1f
jb 2f
dec cx
jmp 1f
2:
inc cx
1:
mov ax,cx
pop bx
ret