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Elite on the BBC Micro and NES

Maths (Arithmetic): SQUA

[BBC Micro disc version, Docked]

Name: SQUA [Show more] Type: Subroutine Category: Maths (Arithmetic) Summary: Clear bit 7 of A and calculate (A P) = A * A
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * NORM calls SQUA

Do the following multiplication of unsigned 8-bit numbers, after first clearing bit 7 of A: (A P) = A * A
.SQUA AND #%01111111 \ Clear bit 7 of A and fall through into SQUA2 to set \ (A P) = A * A