FS#1604 : Faster rolo

FS#1604 - Faster rolo_load

Attached to Project: Rockbox
Opened by Magnus Holmgren (learman) - Saturday, 09 August 2003, 13:40 GMT
Last edited by Jörg Hohensohn (hohensoh) - Sunday, 12 October 2003, 16:42 GMT

Task Type	Patches
Category
Status	Closed
Assigned To	Jörg Hohensohn (hohensoh)
Operating System
Severity	Low
Priority	Normal
Reported Version
Due in Version	Undecided
Due Date	Undecided
Percent Complete
Votes	0
Private	No

Details

This patch speeds up the rolo_load function, by
implementing the descrambling part in assembler (and in
a more efficient form). Also, the descrambling
calculates the checksum as it goes, saving a little
more time. Descrambling time is reduced from about 1.6
to 0.3 seconds (on a player, with a .mod file on
122,534 bytes).

As the patch also moves the "critical" part of
rolo_load to the internal RAM (this, including
descrambling and checksumming, needs 88 bytes), the
.topcode section is removed.

descramble.S is attached separately, because I don't
know how to make cvs diff include it in the patch... :/

descramble.S (3.2 KiB)

descramble.S (3.8 KiB)

rolo.patch (5.2 KiB)

This task depends upon

Closed by Jörg Hohensohn (hohensoh)
Sunday, 12 October 2003, 16:42 GMT
Reason for closing: Accepted