mirror of
https://github.com/mgcaret/of816.git
synced 2024-11-10 15:05:39 +00:00
385 lines
9.8 KiB
ArmAsm
385 lines
9.8 KiB
ArmAsm
|
|
; Math Library - I don't reinvent the wheel here for multiplication, division, etc.
|
|
; others have done great work before me and I credit them when I know who did it.
|
|
|
|
; 32-bit signed comparison
|
|
; C and Z reflect same comparision results as CMP instruction
|
|
.proc _stest32
|
|
lda STACKBASE+6,x
|
|
eor STACKBASE+2,x
|
|
bpl samesign
|
|
lda STACKBASE+4,x
|
|
cmp STACKBASE+0,x
|
|
lda STACKBASE+6,x
|
|
sbc STACKBASE+2,x
|
|
bvs :+
|
|
eor #$8000
|
|
: sec
|
|
rol
|
|
rts
|
|
samesign: lda STACKBASE+6,x
|
|
cmp STACKBASE+2,x
|
|
bcc :+ ; less than or not equal, done
|
|
bne :+
|
|
lda STACKBASE+4,x
|
|
cmp STACKBASE+0,x
|
|
: rts
|
|
.endproc
|
|
|
|
.proc _invertay
|
|
pha
|
|
tya
|
|
eor #$FFFF
|
|
tay
|
|
pla
|
|
eor #$FFFF
|
|
rts
|
|
.endproc
|
|
|
|
.proc _negateay
|
|
pha
|
|
tya
|
|
eor #$FFFF
|
|
clc
|
|
adc #$0001
|
|
tay
|
|
pla
|
|
eor #$FFFF
|
|
adc #$0000
|
|
rts
|
|
.endproc
|
|
|
|
.proc _invert
|
|
lda STACKBASE+0,x
|
|
eor #$FFFF
|
|
sta STACKBASE+0,x
|
|
lda STACKBASE+2,x
|
|
eor #$FFFF
|
|
sta STACKBASE+2,x
|
|
rts
|
|
.endproc
|
|
|
|
.proc _negate
|
|
jsr _invert
|
|
inc STACKBASE+0,x
|
|
bne :+
|
|
inc STACKBASE+2,x
|
|
: rts
|
|
.endproc
|
|
|
|
.proc _dinvert
|
|
jsr _invert
|
|
lda STACKBASE+4,x
|
|
eor #$FFFF
|
|
sta STACKBASE+4,x
|
|
lda STACKBASE+6,x
|
|
eor #$FFFF
|
|
sta STACKBASE+6,x
|
|
rts
|
|
.endproc
|
|
|
|
.proc _dnegate
|
|
jsr _dinvert
|
|
inc STACKBASE+4,x
|
|
bne :+
|
|
inc STACKBASE+6,x
|
|
bne :+
|
|
inc STACKBASE+0,x
|
|
bne :+
|
|
inc STACKBASE+2,x
|
|
: rts
|
|
.endproc
|
|
|
|
.proc _2abs
|
|
bit STACKBASE+2,x
|
|
bpl :+
|
|
jsr _negate
|
|
: jsr _swap
|
|
; fall-through
|
|
.endproc
|
|
|
|
.proc _abs
|
|
bit STACKBASE+2,x
|
|
bpl :+
|
|
jsr _negate
|
|
: rts
|
|
.endproc
|
|
|
|
.proc _signum
|
|
ldy #$FFFF
|
|
lda STACKBASE+2,x
|
|
bpl :+
|
|
sty STACKBASE+2,x
|
|
bra done
|
|
: iny
|
|
stz STACKBASE+2,x
|
|
ora STACKBASE+0,x
|
|
beq done
|
|
iny
|
|
done: sty STACKBASE+0,x
|
|
rts
|
|
.endproc
|
|
|
|
; 32-bit unsigned multiplication with 64-bit result
|
|
; right-shifting version by dclxvi
|
|
; scratch in YR, YR+2 (preserved)
|
|
.proc _umult
|
|
N = YR
|
|
lda N+2
|
|
pha
|
|
lda N
|
|
pha
|
|
lda #$00
|
|
sta N
|
|
ldy #32
|
|
lsr STACKBASE+6,x
|
|
ror STACKBASE+4,x
|
|
l1: bcc l2
|
|
clc
|
|
sta N+2
|
|
lda N
|
|
adc STACKBASE+0,x
|
|
sta N
|
|
lda N+2
|
|
adc STACKBASE+2,x
|
|
l2: ror
|
|
ror N
|
|
ror STACKBASE+6,x
|
|
ror STACKBASE+4,x
|
|
dey
|
|
bne l1
|
|
sta STACKBASE+2,x
|
|
lda N
|
|
sta STACKBASE+0,x
|
|
pla
|
|
sta N
|
|
pla
|
|
sta N+2
|
|
rts
|
|
.endproc
|
|
|
|
; 64-bit divided by 32-bit with 32-bit quotient and remainder
|
|
; Adapted from Garth's routine, just like everyone else :-)
|
|
; carry set if divison by zero or overflow
|
|
; ( d n -- r q )
|
|
; d.hi = stack(4,6), d.low = stack(8,10), n=stack(0,2)
|
|
.proc _umdivmod
|
|
CARRY = YR
|
|
SCRATCH = YR+2
|
|
.if 1 ; shortcut 32-bit by 32-bit division
|
|
lda STACKBASE+4,x
|
|
ora STACKBASE+6,x
|
|
beq _udivmod32 ; go do faster 32-bit divide
|
|
.endif
|
|
lda SCRATCH
|
|
pha
|
|
lda CARRY
|
|
pha
|
|
sec ; first, check for overflow and division by 0
|
|
lda STACKBASE+4,x
|
|
sbc STACKBASE+0,x
|
|
lda STACKBASE+6,x
|
|
sbc STACKBASE+2,x
|
|
bcs overflow
|
|
lda #33 ; 32 bits + 1
|
|
sta XR
|
|
loop: rol STACKBASE+8,x
|
|
rol STACKBASE+10,x
|
|
dec XR
|
|
beq done
|
|
rol STACKBASE+4,x
|
|
rol STACKBASE+6,x
|
|
stz CARRY
|
|
rol CARRY
|
|
sec
|
|
lda STACKBASE+4,x
|
|
sbc STACKBASE+0,x
|
|
sta SCRATCH
|
|
lda STACKBASE+6,x
|
|
sbc STACKBASE+2,x
|
|
tay
|
|
lda CARRY
|
|
sbc #0
|
|
bcc loop
|
|
lda SCRATCH
|
|
sta STACKBASE+4,x
|
|
sty STACKBASE+6,x
|
|
bra loop
|
|
overflow: sec
|
|
bra done1
|
|
done: clc
|
|
inx ; drop
|
|
inx
|
|
inx
|
|
inx
|
|
done1: pla
|
|
sta CARRY
|
|
pla
|
|
sta SCRATCH
|
|
bcs :+ ; leave stack intact if exception
|
|
jmp _swap1
|
|
: rts
|
|
.endproc
|
|
|
|
; 32-bit by 32-bit division
|
|
; assumes that the second stack entry is zero
|
|
; ( d n -- r q ) where d.hi is zero e.g. ( n1 0 n2 -- r q )
|
|
; d.hi = stack(4,6) = 0, d.low = n1 = stack(8,10), n2 = stack(0,2)
|
|
.proc _udivmod32
|
|
lda #32
|
|
sta XR
|
|
l1: asl STACKBASE+8,x ; shift high bit of n1 into r
|
|
rol STACKBASE+10,x ; clearing the low bit for q
|
|
rol STACKBASE+4,x ; r.lo
|
|
rol STACKBASE+6,x ; r.hi
|
|
lda STACKBASE+4,x ; r.lo
|
|
sec ; trial subraction
|
|
sbc STACKBASE+0,x ; n2.lo
|
|
tay ; save low word
|
|
lda STACKBASE+6,x ; r.hi
|
|
sbc STACKBASE+2,x ; n2.hi
|
|
bcc l2 ; subtraction succeeded?
|
|
sta STACKBASE+6,x ; r.hi yes, save result
|
|
sty STACKBASE+4,x ; r.lo
|
|
inc STACKBASE+8,x ; n1.lo and record a 1 in the quotient
|
|
l2: dec XR ; next bit
|
|
bne l1
|
|
inx ; kill of top stack item
|
|
inx
|
|
inx
|
|
inx
|
|
clc ; this *never* overflows
|
|
jmp _swap1
|
|
.endproc
|
|
|
|
; ( d n -- ud u )
|
|
.proc _dnabs
|
|
lda STACKBASE+2,x ; take absolute value of n1
|
|
bpl :+
|
|
jsr _negate
|
|
: lda STACKBASE+6,x ; take absolute value of d
|
|
bpl :+
|
|
dtneg: inx
|
|
inx
|
|
inx
|
|
inx
|
|
jsr _dnegate
|
|
dex
|
|
dex
|
|
dex
|
|
dex
|
|
: rts
|
|
.endproc
|
|
_dtucknegate = _dnabs::dtneg
|
|
|
|
.proc _smdivrem
|
|
lda STACKBASE+6,x ; save dividend sign in MSW of high cell of d
|
|
pha
|
|
eor STACKBASE+2,x ; compute result sign and save
|
|
pha
|
|
jsr _dnabs ; take absolute value of arguments
|
|
jsr _umdivmod
|
|
bcs overflow ; overflow
|
|
pla ; see if we should negate quotient
|
|
bpl :+
|
|
jsr _negate ; make it negative
|
|
: pla ; get dividend sign
|
|
bpl :+
|
|
tneg: inx ; negate remainder if it should be negative
|
|
inx
|
|
inx
|
|
inx
|
|
jsr _negate
|
|
dex
|
|
dex
|
|
dex
|
|
dex
|
|
: clc
|
|
rts
|
|
overflow: pla ; carry is set, pla does not affect it
|
|
pla
|
|
rts
|
|
.endproc
|
|
_tucknegate = _smdivrem::tneg
|
|
|
|
.proc _fmdivmod
|
|
stz WR
|
|
lda STACKBASE+2,x
|
|
bpl :+
|
|
dec WR
|
|
jsr _dnabs
|
|
: lda STACKBASE+6,x
|
|
bpl :+
|
|
lda STACKBASE+0,x
|
|
clc
|
|
adc STACKBASE+4,x
|
|
sta STACKBASE+4,x
|
|
lda STACKBASE+2,x
|
|
adc STACKBASE+6,x
|
|
sta STACKBASE+6,x
|
|
: jsr _umdivmod
|
|
bcs :+
|
|
bit WR
|
|
bpl :+
|
|
jsr _tucknegate ; clears carry
|
|
: rts
|
|
.endproc
|
|
|
|
; adapted from Lee Davidson routine
|
|
; ( u1 -- u1 u2 ) u1 = closest integer <= square root, u2 = remainder
|
|
; number popped into WR,WR+2
|
|
; remainder on stack, offsets 0,2
|
|
; root on stack, offsets 4,6
|
|
; temp in YR
|
|
; counter in XR
|
|
.proc _sqroot
|
|
jsr _peekwr ; get number into WR
|
|
jsr _stackdecr ; make room for remainder
|
|
lda #16 ; pairs of bits
|
|
sta XR ; counter
|
|
lda #$0000
|
|
sta STACKBASE+0,x ; init remainder
|
|
sta STACKBASE+2,x
|
|
sta STACKBASE+4,x ; init root
|
|
sta STACKBASE+6,x
|
|
|
|
lp: asl STACKBASE+4,x ; root = root * 2
|
|
asl WR ; now shift 2 bits of number into remainder
|
|
rol WR+2
|
|
rol STACKBASE+0,x
|
|
rol STACKBASE+2,x
|
|
asl WR
|
|
rol WR+2
|
|
rol STACKBASE+0,x
|
|
rol STACKBASE+2,x
|
|
lda STACKBASE+4,x ; copy root into temp
|
|
sta YR
|
|
lda STACKBASE+6,x ; (a bit shorter than immediate load)
|
|
sta YR+2
|
|
sec ; +1
|
|
rol YR ; temp = temp * 2 + 1
|
|
rol YR+2
|
|
lda STACKBASE+2,x ; compare remainder with partial
|
|
cmp YR+2
|
|
bcc next ; skip sub if remainder smaller
|
|
bne subtr ; but do it if equal
|
|
lda STACKBASE+0,x
|
|
cmp YR
|
|
bcc next ; same deal
|
|
subtr: lda STACKBASE+0,x ; subtract partial from remainder
|
|
sbc YR
|
|
sta STACKBASE+0,x
|
|
lda STACKBASE+2,X
|
|
sbc YR+2
|
|
sta STACKBASE+2,x
|
|
inc STACKBASE+4,x ; no need to increment high word, always zero
|
|
next: dec XR
|
|
bne lp
|
|
rts
|
|
.endproc
|
|
|
|
|
|
|
|
|
|
|