Sorry Keith,

Your Swap regsiters R0-R3 with R4-R7 example does not work properly. Please have a look at your routine.

For example, you have to move the value
from accumulator to R0, not from R0 to R4
etc. Besides, you changed the accumulator
content.

This fragment is much better:

swap_r0r3_r4r7: ; Acc R0 R4
xch a,r0 ; 00 aa 44
xch a,r4 ; 44 aa 00
xch a,r0 ; aa 44 00

Regards,
George


; kef762@yahoo.com
; http://www.tigerprecision.com
;
swap_r0r3_r4r7: ; Acc R0 R4
mov a,r0 ; 00 00 44
xch a,r4 ; 44 00 44
mov r4,0x00 ; 44 00 00
mov a,r1
xch a,r5
mov r5,0x01
mov a,r2
xch a,r6
mov r6,0x02
mov a,r3
xch a,r7
mov r7,0x03
ret