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Implement fmax and fmin.

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Stephen Heumann 2021-11-23 18:54:18 -06:00
parent 14908ebcd6
commit ce05615a63
1 changed files with 152 additions and 0 deletions
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152
math2.asm
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@ -459,6 +459,158 @@ ret plx clean up stack
rtl
end
****************************************************************
*
* double fmax(double x, double y);
*
* Returns the maximum numeric value of x or y.
* If one is a NaN, returns the other.
*
****************************************************************
*
fmax start
fmaxf entry
fmaxl entry
using MathCommon2
phb
phk
plb
phd
tsc set up direct page
clc
adc #7
tcd
pea 0 compare x and y
pha
clc
adc #10
pea 0
pha
FCMPX
bmi use_y if x < y, return y
bvs use_x if x >= y, return x
beq use_x
pea 0 if x,y are unordered
phd
FCLASSX
txa
and #$00FE
cmp #$00FC if x is not a nan, return x
beq use_y else return y
use_x ldx #0
bra copyit
use_y ldx #10
copyit lda 0,x copy result to t1
sta t1
lda 2,x
sta t1+2
lda 4,x
sta t1+4
lda 6,x
sta t1+6
lda 8,x
sta t1+8
pld clean up stack
plx
ply
tsc
clc
adc #20
tcs
phy
phx
plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double fmin(double x, double y);
*
* Returns the minimum numeric value of x or y.
* If one is a NaN, returns the other.
*
****************************************************************
*
fmin start
fminf entry
fminl entry
using MathCommon2
phb
phk
plb
phd
tsc set up direct page
clc
adc #7
tcd
pea 0 compare x and y
pha
clc
adc #10
pea 0
pha
FCMPX
bmi use_x if x < y, return x
bvs use_y if x >= y, return y
beq use_y
pea 0 if x,y are unordered
phd
FCLASSX
txa
and #$00FE
cmp #$00FC if x is not a nan, return x
beq use_y else return y
use_x ldx #0
bra copyit
use_y ldx #10
copyit lda 0,x copy result to t1
sta t1
lda 2,x
sta t1+2
lda 4,x
sta t1+4
lda 6,x
sta t1+6
lda 8,x
sta t1+8
pld clean up stack
plx
ply
tsc
clc
adc #20
tcs
phy
phx
plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* int ilogb(double x);