CompuServe Messages

The operation you speak of, being a BYTE oriented move, would be improved by making it a WORD or LONG operation, regardless of processor. Comparing a MOVEM with repetetive MOVE.L shows a large gain in speed on a 68000. Not too sure what the difference would be, if any, on a 68010 using the DBRA. As for actually writing the routine, it isn't such a tough one. Say I have (through saving the registers I need with a MOVEM, to be restored after the operation) 8 registers available. Also suppose i know that the transfer is always 512 bytes (this is a rela life case), and that the source block is always longword aligned. First, I check the alignment of the destination. If it is even, I can simply set up a counter for the DBRA, then… MOVEM.L source,reglist MOVEM.L reglist,dest ADD #8,source ADD #8,dest DBRA back to the label I forgot to put in. If the alignment needs work, I simply transfer 1 byte, transfer a large block, (getting as close as I can within the 8 bytes at a time limitation), transfer a smale even number, then 1 nore byte to make it work out even. If the destination is always even, this techniques will increase the transfer rate by a large amount. The hard disk driver I am working on improved by about 8 or 9K per second using it, and on pure memory moves, a much greater speed increase woud be realized.