Apple-2gs-SW/ORCALib
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Add real to long long conversion routines.

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For conversion to signed long long, we can almost just use SANE's FX2C call to convert it to comp. But LLONG_MIN corresponds to the bit pattern of the comp NaN, so it has to be treated specially. (You might think SANE would return the comp NaN when converting out-of-range values, which would give the value we want, but somewhat strangely it does not.)

For conversion to unsigned long long, we check if the value is greater than LLONG_MAX (which is also the max comp value). If so, we subtract LLONG_MAX+1 from the floating-point value before conversion and add it back in to the integer afterward.
This commit is contained in:
Stephen Heumann 2021-02-16 18:44:38 -06:00
parent 81e152f863
commit f9d7017687
2 changed files with 152 additions and 1 deletions
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129
int64.asm
View File

@ -614,7 +614,7 @@ exponent equ mantissa+8 biased exponent and sign bit
ldy #0 default sign bit is 0 (positive)
lda mantissa+6 if mantissa is negative then
bpl lb0
negate8 mantissa negate it
negate8 mantissa negate it
ldy #$8000 sign bit is 1 (negative)
lb0 tya set sign
@ -634,3 +634,130 @@ lp1 dec exponent normalize number
ret pld
rtl
end
****************************************************************
*
* ~CnvRealLongLong - convert an extended SANE real into
* a long long integer
*
* Inputs:
* extended real on stack
*
* Outputs:
* signed long long int on stack
*
****************************************************************
*
~CnvRealLongLong start
tsc
clc
adc #4
pea 0 push src address for fcpxx
pha
pea llmin|-16 push dst address for fcpxx
pea llmin
pea 0 push operand address for ftintx
pha
ftintx round
fcpxx compare with LLONG_MIN
bne convert
lda #$8000 if it is LONG_MIN, use that value
sta 12,s
asl a
sta 10,s
sta 8,s
sta 6,s
bra done
convert tsc if it is not LONG_MIN, call fx2c:
clc
adc #4
pea 0 push src address for fx2c
pha
pea 0 push dst address for fx2c
inc a
inc a
pha
fx2c convert
done phb move return address
pla
plx
ply
phx
pha
plb
rtl
llmin dc e'-9223372036854775808'
end
****************************************************************
*
* ~CnvRealULongLong - convert an extended SANE real into
* an unsigned long long integer
*
* Inputs:
* extended real on stack
*
* Outputs:
* unsigned long long int on stack
*
****************************************************************
*
~CnvRealULongLong start
pea 0 initially assume val <= LLONG_MAX
tsc
clc
adc #6
pea 0 push src address for fcpxx
pha
pea llbig|-16 push dst address for fcpxx
pea llbig
pea 0 push operand address for ftintx
pha
ftintx round
fcpxx compare with LLONG_MAX+1
bmi convert
lda #1 if val > LLONG_MAX:
sta 1,S save flag to indicate this
tsc
clc
adc #6
pea llbig|-16 push src address for fsubx
pea llbig
pea 0 push dst address for fsubx
pha
fsubx val -= LLONG_MAX+1
convert tsc
clc
adc #6
pea 0 push src address for fx2c
pha
pea 0 push dst address for fx2c
inc a
inc a
pha
fx2c convert val as comp
pla if orig val was > LLONG_MAX:
beq done
lda 12,s
eor #$8000
sta 12,s result += LLONG_MAX+1
done phb move return address
pla
plx
ply
phx
pha
plb
rtl
llbig dc e'9223372036854775808'
end

24
int64.macros
View File

@ -140,3 +140,27 @@
.d
sta 2+&op
mend
MACRO
&LAB FTINTX
&LAB PEA $0016
LDX #$090A
JSL $E10000
MEND
MACRO
&LAB FX2C
&LAB PEA $0510
LDX #$090A
JSL $E10000
MEND
MACRO
&LAB FCPXX
&LAB PEA $0A
LDX #$090A
JSL $E10000
MEND
MACRO
&LAB FSUBX
&LAB PEA 2
LDX #$090A
JSL $E10000
MEND