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22 lines
487 B
ArmAsm
22 lines
487 B
ArmAsm
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; 16-bit subtraction simple example by FMan/Tropyx
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; modified by rkujawa
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.org 0xC000
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.set num1lo, 0x62
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.set num1hi, 0x63
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.set num2lo, 0x64
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.set num2hi, 0x65
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.set reslo, 0x66
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.set reshi, 0x67
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; subtracts number 2 from number 1 and writes result out
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sub: sec ; set carry for borrow purpose
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lda num1lo
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sbc num2lo ; perform subtraction on the LSBs
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sta reslo
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lda num1hi ; do the same for the MSBs, with carry
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sbc num2hi ; set according to the previous result
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sta reshi
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stp
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