Tutorial: How to put inline assembly functions into ZX Basic

[britlion]

Up on WOS, someone schooled me.

This code will apparently mirror a byte as well. Still trying to get my head round the logic! (and if it works)

Code:

;17 bytes and 66 clock cycles Reverse: ld b,a ;b=ABCDEFGH rrca ;a=HABCDEFG rrca ;a=GHABCDEF xor b \ and %10101010 \ xor b ;a=GBADCFEH ld b,a ;b=GBADCFEH rrca ;a=HGBADCFE rrca ;a=EHGBADCF rrca ;a=FEHGBADC rrca ;a=CFEHGBAD xor b \ and %01100110 \ xor b ;a=GFEDCBAH rrca ;a=HGFEDCBA

n=0
n A B
0 0 0 -> 0 = B
0 0 1 -> 1 = B
0 1 0 -> 0 = B
0 1 1 -> 1 = B

n=1
1 0 0 -> 0 = A
1 0 1 -> 0 = A
1 1 0 -> 1 = A
1 1 1 -> 1 = A

a XOR b and n xor b


aaaaaaaa xor bbbbbbbb and 10101010 xor bbbbbbbb = abababab