ORCALib/math2.asm
Stephen Heumann 3ec8a8797f Implement some of the math functions added in C99.
The functions implemented so far are largely the ones that map (nearly) directly to SANE calls.

Note that C99 specifies separate float/double/long double versions of each of these functions, but under ORCA/C they generally use the same code.
2021-11-20 19:24:51 -06:00

842 lines
17 KiB
NASM

keep obj/math2
mcopy math2.macros
case on
****************************************************************
*
* Math2 - additional math routines
*
* This code provides additional functions from <math.h>
* (including internal helper functions used by macros),
* supplementing the ones in SysFloat.
*
****************************************************************
math2 private dummy segment
end
****************************************************************
*
* MathCommon2 - common work areas for the math library
*
****************************************************************
*
MathCommon2 privdata
;
; temporary work space/return value
;
t1 ds 10
end
****************************************************************
*
* int __fpclassifyf(float x);
*
* Classify a float value
*
* Inputs:
* val - the number to classify
*
* Outputs:
* one of the FP_* classification values
*
****************************************************************
*
__fpclassifyf start
csubroutine (10:val),0
tdc
clc
adc #val
ldy #0
phy
pha
phy
pha
phy
pha
FX2S
FCLASSS
txa
and #$00FF
cmp #$00FC
bne lb1
inc a
lb1 sta val
creturn 2:val
end
****************************************************************
*
* int __fpclassifyd(double x);
*
* Classify a double value
*
* Inputs:
* val - the number to classify
*
* Outputs:
* one of the FP_* classification values
*
****************************************************************
*
__fpclassifyd start
csubroutine (10:val),0
tdc
clc
adc #val
ldy #0
phy
pha
phy
pha
phy
pha
FX2D
FCLASSD
txa
and #$00FF
cmp #$00FC
bne lb1
inc a
lb1 sta val
creturn 2:val
end
****************************************************************
*
* int __fpclassifyl(long double x);
*
* Classify a long double value
*
* Inputs:
* val - the number to classify
*
* Outputs:
* one of the FP_* classification values
*
****************************************************************
*
__fpclassifyl start
csubroutine (10:val),0
tdc
clc
adc #val
pea 0
pha
FCLASSX
txa
and #$00FF
cmp #$00FC
bne lb1
inc a
lb1 sta val
creturn 2:val
end
****************************************************************
*
* int __signbit(long double x);
*
* Get the sign bit of a floating-point value
*
* Inputs:
* val - the number
*
* Outputs:
* 0 if positive, non-zero if negative
*
****************************************************************
*
__signbit start
csubroutine (10:val),0
lda val+8
and #$8000
sta val
creturn 2:val
end
****************************************************************
*
* int __fpcompare(long double x, long double y, short mask);
*
* Compare two floating-point values, not signaling invalid
* if they are unordered.
*
* Inputs:
* x,y - values to compare
* mask - mask of bits as returned in X register from FCMP
*
* Outputs:
* 1 if x and y have one of the relations specified by mask
* 0 otherwise
*
****************************************************************
*
__fpcompare start
csubroutine (10:x,10:y,2:mask),0
tdc
clc
adc #x
pea 0
pha
tdc
clc
adc #y
pea 0
pha
FCMPX
txa
and mask
beq lb1
lda #1
lb1 sta mask
creturn 2:mask
end
****************************************************************
*
* double cbrt(double x);
*
* Returns x^(1/3) (the cube root of x).
*
****************************************************************
*
cbrt start
cbrtf entry
cbrtl entry
using MathCommon2
phb place the number in a work area
plx (except exponent/sign word)
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla get exponent/sign word
phy
phx
pha save original sign
and #$7FFF
sta t1+8 force sign to +
ph4 #onethird compute abs(x)^(1/3)
ph4 #t1
FXPWRY
pla if sign of x was -
bpl ret
lda t1+8
ora #$8000
sta t1+8 set sign of result to -
ret plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
onethird dc e'0.33333333333333333333'
end
****************************************************************
*
* double copysign(double x, double y);
*
* Returns a value with the magnitude of x and the sign of y.
*
****************************************************************
*
copysign start
copysignf entry
copysignl entry
using MathCommon2
phb place x in a work area...
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
asl a ...with the sign bit shifted off
sta t1+8
pla remove y
pla
pla
pla
pla
asl a get sign bit of y
ror t1+8 give return value that sign
phy
phx
plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double exp2(double x);
*
* Returns 2^x.
*
****************************************************************
*
exp2 start
exp2f entry
exp2l entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FEXP2X
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double expm1(double x);
*
* Returns e^x - 1.
*
****************************************************************
*
expm1 start
expm1f entry
expm1l entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FEXP1X
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* int ilogb(double x);
*
* Returns the binary exponent of x (a signed integer value),
* treating denormalized numbers as if they were normalized.
* Handles inf/nan/0 cases specially.
*
****************************************************************
*
ilogb start
ilogbf entry
ilogbl entry
csubroutine (10:x),0
tdc check for special cases
clc
adc #x
pea 0
pha
FCLASSX
ldy #$7FFF
txa
and #$FF
cmp #$FE if x is INF
beq special return INT_MAX
lsr a
beq do_logb if x is 0 or NAN
iny return INT_MIN
special sty x
bra ret
do_logb tdc compute logb(x)
clc
adc #x
pea 0
pha
FLOGBX
tdc convert to integer
clc
adc #x
pea 0
pha
pea 0
pha
FX2I
ret creturn 2:x return it
rtl
end
****************************************************************
*
* double log1p(double x);
*
* Returns ln(1+x).
*
****************************************************************
*
log1p start
log1pf entry
log1pl entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FLN1X
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double log2(double x);
*
* Returns log2(x) (the base-2 logarithm of x).
*
****************************************************************
*
log2 start
log2f entry
log2l entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FLOG2X
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double logb(double x);
*
* Returns the binary exponent of x (a signed integer value),
* treating denormalized numbers as if they were normalized.
*
****************************************************************
*
logb start
logbf entry
logbl entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FLOGBX
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* long lrint(double x);
*
* Rounds x to an integer using current rounding direction
* and returns it as a long (if representable).
*
****************************************************************
*
lrint start
lrintf entry
lrintl entry
csubroutine (10:x),0
tdc convert to integer
clc
adc #x
pea 0
pha
pea 0
pha
FX2L
ret creturn 4:x return it
rtl
end
****************************************************************
*
* double remainder(double x, double y);
*
* Returns x REM y as specified by IEEE 754: r = x - ny,
* where n is the integer nearest to the exact value of x/y.
* When x/y is halfway between two integers, n is even.
* If r = 0, its sign is that of x.
*
****************************************************************
*
remainder start
remainderf entry
remainderl entry
using MathCommon2
phb place x in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
tsc compute the value
clc
adc #5
pea 0
pha
ph4 #t1
FREMX
pla move return address
sta 9,s
pla
sta 9,s
tsc
clc
adc #6
tcs
plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double remquo(double x, double y, int *quo);
*
* Returns x REM y as specified by IEEE 754 (like remainder).
* Also, sets *quo to a value whose sign is the same as x/y
* and whose magnitude gives the low-order 7 bits of the
* magnitude of the integer quotient x/y.
*
****************************************************************
*
remquo start
remquof entry
remquol entry
using MathCommon2
phb place x in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
tsc compute the value
clc
adc #5
pea 0
pha
ph4 #t1
FREMX
phd
php save sign flag
tsc
tcd
txa calculate value to store in *quo
and #$007F
plp
bpl setquo
eor #$FFFF
inc a
setquo sta [18] store it
pld
pla move return address
sta 13,s
pla
sta 13,s
tsc
clc
adc #10
tcs
plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double rint(double x);
*
* Rounds x to an integer using current rounding direction.
*
****************************************************************
*
rint start
rintf entry
rintl entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FRINTX
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double scalbn(double x, int n);
*
* Returns x * 2^n.
*
****************************************************************
*
scalbn start
scalbnf entry
scalbnl entry
using MathCommon2
phb place x in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
pla get n
phy
phx
pha compute the value
ph4 #t1
FSCALBX
plb
ldx #^t1 return a pointer to the result
lda #t1
rtl
end
****************************************************************
*
* double trunc(double x);
*
* Truncates x to an integer (discarding fractional part).
*
****************************************************************
*
trunc start
truncf entry
truncl entry
using MathCommon2
phb place the number in a work area
plx
ply
phk
plb
pla
sta t1
pla
sta t1+2
pla
sta t1+4
pla
sta t1+6
pla
sta t1+8
phy
phx
plb
ph4 #t1 compute the value
FTINTX
ldx #^t1 return a pointer to the result
lda #t1
rtl
end