fix melody for voices 3 and 4 15 months later, I took another look at why the music was off for channels 3 and 4 and pretty fast noticed that it affects only the voices using the mod3 subroutine. Executing mod3 with simavr[1] showed that the compare-branch step is broken. Switching BRPL for the correct BRCS fixed the problem. [1]: in the hackiest way imaginable: gdb> layout regs gdb> set $r24 = 0x15 # test value for Mh gdb> set $r23 = 0x16 # test value for Ml gdb> set $pc = 0x1a # start of mod3 routine gdb> ni # repeatedly