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improved sqrt16

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This commit is contained in:
Irmen de Jong 2020-11-01 05:45:49 +01:00
parent 47cbc7b1f9
commit 95c0425151
2 changed files with 51 additions and 66 deletions
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75
compiler/res/prog8lib/prog8_lib.asm
View File

@ -708,53 +708,40 @@ func_sqrt16_into_A .proc
.pend
func_sqrt16 .proc
; TODO is this one faster? http://6502org.wikidot.com/software-math-sqrt
; integer square root from http://6502org.wikidot.com/software-math-sqrt
txa
pha
lda P8ESTACK_LO+1,x
sta P8ZP_SCRATCH_W2
lda P8ESTACK_HI+1,x
sta P8ZP_SCRATCH_W2+1
stx P8ZP_SCRATCH_REG
ldy #$00 ; r = 0
ldx #$07
clc ; clear bit 16 of m
_loop
tya
ora _stab-1,x
sta P8ZP_SCRATCH_B1 ; (r asl 8) | (d asl 7)
lda P8ZP_SCRATCH_W2+1
bcs _skip0 ; m >= 65536? then t <= m is always true
cmp P8ZP_SCRATCH_B1
bcc _skip1 ; t <= m
_skip0
sbc P8ZP_SCRATCH_B1
sta P8ZP_SCRATCH_W2+1 ; m = m - t
tya
ora _stab,x
tay ; r = r or d
_skip1
asl P8ZP_SCRATCH_W2
rol P8ZP_SCRATCH_W2+1 ; m = m asl 1
dex
bne _loop
; last iteration
bcs _skip2
sty P8ZP_SCRATCH_B1
lda P8ZP_SCRATCH_W2
cmp #$80
lda P8ZP_SCRATCH_W2+1
sbc P8ZP_SCRATCH_B1
bcc _skip3
_skip2
iny ; r = r or d (d is 1 here)
_skip3
ldx P8ZP_SCRATCH_REG
tya
sta P8ESTACK_LO+1,x
ldy P8ESTACK_HI+1,x
sta P8ZP_SCRATCH_W1
sty P8ZP_SCRATCH_W1+1
lda #0
sta P8ESTACK_HI+1,x
sta P8ZP_SCRATCH_B1
sta P8ZP_SCRATCH_REG
ldx #8
- sec
lda P8ZP_SCRATCH_W1+1
sbc #$40
tay
lda P8ZP_SCRATCH_REG
sbc P8ZP_SCRATCH_B1
bcc +
sty P8ZP_SCRATCH_W1+1
sta P8ZP_SCRATCH_REG
+ rol P8ZP_SCRATCH_B1
asl P8ZP_SCRATCH_W1
rol P8ZP_SCRATCH_W1+1
rol P8ZP_SCRATCH_REG
asl P8ZP_SCRATCH_W1
rol P8ZP_SCRATCH_W1+1
rol P8ZP_SCRATCH_REG
dex
bne -
pla
tax
lda P8ZP_SCRATCH_B1
sta P8ESTACK_LO+1,x
rts
_stab .byte $01,$02,$04,$08,$10,$20,$40,$80
.pend

42
examples/test.p8
View File

@ -1,5 +1,4 @@
%import textio
%import floats
%import syslib
%zeropage basicsafe
@ -9,29 +8,28 @@
main {
sub start() {
float[] fls = [1.1, 2.2, 0.0, 4.4, 3.3]
float fl
ubyte ii
uword num
ubyte ss
fls[2] = sin(fls[0])
for ii in 0 to len(fls)-1 {
floats.print_f(fls[ii])
txt.chrout('\n')
}
num = 65535
ss = sqrt16(num)
txt.print_ub(ss)
txt.chrout('\n')
fls[3] = cos(fls[0])
for ii in 0 to len(fls)-1 {
floats.print_f(fls[ii])
txt.chrout('\n')
}
num = 20000
ss = sqrt16(num)
txt.print_ub(ss)
txt.chrout('\n')
num = 9999
ss = sqrt16(num)
txt.print_ub(ss)
txt.chrout('\n')
; fl = getfloat()
;
; floats.print_f(fl)
; txt.chrout('\n')
num = 500
ss = sqrt16(num)
txt.print_ub(ss)
txt.chrout('\n')
testX()
}
@ -45,9 +43,9 @@ main {
return "foobar"
}
; sub getfloat() -> float {
; return 4.56789
; }
sub getfloat() -> float {
return 123.456789
}
sub mcp(uword from, uword dest, ubyte length) {
txt.print_uw(from)