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Add a comparison routine for signed 64-bit numbers.

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This is almost the same as ~CMP8 in SysLib, except that it does not use a static location to save the DP. This makes it slightly smaller/faster, and also makes it thread/interrupt safe.
This commit is contained in:
Stephen Heumann 2021-02-15 18:06:54 -06:00
parent 6bf27c6743
commit 81e152f863
1 changed files with 56 additions and 0 deletions
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56
int64.asm
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@ -326,6 +326,62 @@ DV11 LDA ANS,X
RTL
END
****************************************************************
*
* ~SCMP8 - Eight Byte Signed Integer Compare
*
* Inputs:
* NUM1 - first argument
* NUM2 - second argument
*
* Outputs:
* C - set if NUM1 >= NUM2, else clear
* Z - set if NUM1 = NUM2, else clear
*
****************************************************************
*
~SCMP8 START
NUM1 EQU 12 first argument
NUM2 EQU 4 second argument
RETURN EQU 0 P reg and return addr
TDC set up DP
TAX
TSC
TCD
LDA NUM1+6 if numbers are of opposite sign then
EOR NUM2+6
BPL LB1
LDA NUM2+6 reverse sense of compare
CMP NUM1+6
BRA LB2 else
LB1 LDA NUM1+6 compare numbers
CMP NUM2+6
BNE LB2
LDA NUM1+4
CMP NUM2+4
BNE LB2
LDA NUM1+2
CMP NUM2+2
BNE LB2
LDA NUM1
CMP NUM2
LB2 ANOP endif
PHP save result
LDA RETURN move P and return addr
STA NUM1+4
LDA RETURN+2
STA NUM1+6
CLC remove 16 bytes from stack
TSC
ADC #16
TCS
TXA restore DP
TCD
PLP restore P
RTL return
END
****************************************************************
*
* ~LShr8 - Shift an unsigned long long value right