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libspeex: Get rid of some bad trickery with the stack pointer.

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Using the stack pointer for anything else than pointing to the
current stack can have in very bad effects, especially on hosted
platforms (e.g. when mixed with signals). Remove this at a
neglible performance cost.

Change-Id: I9545d701bd13c32456c224b87c708d907880c0ff
This commit is contained in:
Thomas Martitz 2012-01-17 15:13:34 +01:00
parent 6d19275876
commit a0d54b09a6
1 changed files with 7 additions and 8 deletions
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15
apps/codecs/libspeex/filters_arm4.S
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@ -206,11 +206,9 @@ qmf_synth:
sub r0, r8, r5 @ r0 = &xx1[N2]
sub r1, r9, r5 @ r1 = &xx2[N2]
str r4, [sp, #-4] @ Stack N
str r4, [sp, #-4]! @ Stack N
mov r4, r5
str r4, [sp, #-8] @ Stack M
@ sp doesn't point to the end of the stack frame from here on, but we're not
@ calling anything so it shouldn't matter
str r4, [sp, #-4]! @ Stack M
@ Main loop, register usage:
@ r0 = xx1, r1 = xx2, r2 = a, r3 = y, r4 = M, r5 = x10, r6 = x11, r7 = x20
@ r8 = x21, r9 = [a1, a0], r10 = acc0, r11 = acc1, r12 = acc2, r14 = acc3
@ -251,7 +249,7 @@ qmf_synth:
subs r4, r4, #4
bne 1b
ldr r4, [sp, #-8] @ r4 = M
ldr r4, [sp] @ r4 = M
sub r2, r2, r4, lsl #1 @ r2 = &a[0]
sub r0, r0, r4 @ r0 = &xx1[N2 - 2 - i]
sub r1, r1, r4 @ r1 = &xx2[N2 - 2 - i]
@ -281,13 +279,14 @@ qmf_synth:
strh r11, [r3], #2
strh r12, [r3], #2
strh r14, [r3], #2
ldr r10, [sp, #-4] @ Load N
ldr r10, [sp, #4] @ Load N
subs r10, r10, #4 @ Are we done?
strne r10, [sp, #-4]
bne 0b
strne r10, [sp, #4] @ no ->
bne 0b @ do outer loop
@ Copy start of xx1 and xx2 back to alternate mem1 and mem2 entries
@ r0 and r1 are &xx1[0] and &xx2[0] at this point
add sp, sp, #8
ldmia sp, { r5-r6, sp } @ Fetch &mem1[1], &mem2[1], restore sp
0:
ldr r7, [r0], #4