\ --- Mod: Code moved for Elite-A: --------------------> \.SPS2 \ \ASL A \ Set X = |A| * 2, and set the C flag to the sign bit of \TAX \ A \ \LDA #0 \ Set Y to have the sign bit from A in bit 7, with the \ROR A \ rest of its bits zeroed, so Y now contains the sign of \TAY \ the original argument \ \LDA #20 \ Set Q = 20 \STA Q \ \TXA \ Copy X into A, so A now contains the argument A * 2 \ \JSR DVID4 \ Calculate the following: \ \ \ \ P = A / Q \ \ = |argument A| * 2 / 20 \ \ = |argument A| / 10 \ \LDX P \ Set X to the result \ \TYA \ If the sign of the original argument A is negative, \BMI LL163 \ jump to LL163 to flip the sign of the result \ \LDY #0 \ Set the high byte of the result to 0, as the result is \ \ positive \ \RTS \ Return from the subroutine \ \.LL163 \ \LDY #&FF \ The result is negative, so set the high byte to &FF \ \TXA \ Flip the low byte and add 1 to get the negated low \EOR #&FF \ byte, using two's complement \TAX \INX \ \RTS \ Return from the subroutine \ --- End of moved code ------------------------------->Name: SPS2, Moved [Show more] Type: Subroutine Category: Maths (Arithmetic) Summary: Calculate (Y X) = A / 10Context: See this subroutine in context in the source code References: No direct references to this subroutine in this source file
Calculate the following, where A is a sign-magnitude 8-bit integer and the result is a signed 16-bit integer: (Y X) = A / 10
Returns: C flag The C flag is cleared