Replaced jump table with a more efficient one.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7658 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thom Johansen 2005-10-27 11:00:24 +00:00
parent 0b38c7dcbe
commit c2628f3af9

View file

@ -48,21 +48,18 @@ lpc_decode_emac:
moveq.l #8, %d3
cmp.l %d3, %d2
jgt .default | order is over 8, jump to default case
lea.l .jumptable, %a4
move.l (%a4, %d2.l*4), %a4
jmp (%a4)
.align 4 | avoid unaligned fetch
jmp.l (2, %pc, %d2.l*4) | jump to loop corresponding to pred_order
.jumptable:
.long .exit
.long .order1
.long .order2
.long .order3
.long .order4
.long .order5
.long .order6
.long .order7
.long .order8
bra.w .exit | zero order filter isn't possible, exit function
bra.w .order1
bra.w .order2
bra.w .order3
bra.w .order4
bra.w .order5
bra.w .order6
bra.w .order7
| last jump table entry coincides with target, so leave it out
.order8:
movem.l (%a1), %d3-%d7/%a2-%a4 | load lpc coefs
move.l (%a0)+, %a5 | load first history sample
@ -78,7 +75,7 @@ lpc_decode_emac:
movclr.l %acc0, %d2 | get sum
asr.l %d1, %d2 | shift sum by lp_quantization bits
add.l %d2, (%a0) | add residual and save
lea.l (-6*4, %a0), %a0 | history pointer points at second element
lea.l (-6*4, %a0), %a0 | point history back at second element
subq.l #1, %d0 | decrement counter
jne .loop8 | are we done?
jra .exit