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quake: clean up asm mixer

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Fixes my ugly formatting.
This commit is contained in:
Franklin Wei 2019-10-07 14:48:21 -04:00
parent 01cccaf2d2
commit c0cc9aa9e8
1 changed files with 46 additions and 63 deletions
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109
apps/plugins/sdl/progs/quake/snd_mix_arm.S
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@ -19,12 +19,14 @@
* *
***************************************************************************/ ***************************************************************************/
/** Sound mixing code for ARM. **/ /*
/* Takes 8-bit mono audio and outputs stereo 16-bit samples. * Sound mixing code for ARM.
* stereo volumes are passed as arguments. *
* * Takes an array of 8-bit mono audio and outputs stereo 16-bit
* Bear with me. This is my first ARM assembly, ever. * samples. Stereo volumes are passed as arguments r0 and r1.
*/ *
* Bear with me. This is my first ARM assembly, ever.
*/
.text .text
.align 2 .align 2
@ -33,93 +35,74 @@
#if defined(__ARM_ARCH_5TEJ__) #if defined(__ARM_ARCH_5TEJ__)
SND_PaintChannelFrom8: SND_PaintChannelFrom8:
// r0: int true_lvol ;; r0: int true_lvol
// r1: int true_rvol ;; r1: int true_rvol
// r2: char *sfx ;; r2: char *sfx
// r3: int count ;; r3: int count
stmfd sp!, {r4, r5, r6, r7, r8, sl} stmfd sp!, {r4, r5, r6, r7, r8, sl}
ldr ip, =paintbuffer ldr ip, =paintbuffer
ldr ip, [ip] ldr ip, [ip]
mov r0, r0, asl #16 // pre-scale both volumes by 2^16 mov r0, r0, asl #16 ; prescale by 2^16
mov r1, r1, asl #16 mov r1, r1, asl #16
sub r3, r3, #1 // we'll count backwards sub r3, r3, #1 ; count backwards
// sl = 0xffff0000
ldrh sl, =0xffff
.loop: ldrh sl, =0xffff ; halfword mask
ldrsb r4, [r2, r3] // load *sfx[i] -> r4
// keep endianness in mind here 1:
// buffer looks like [left_0, left_1, right_0, right_1] in memory ldrsb r4, [r2, r3] ; load input sample
// but it is loaded as [right1, right0, left1, left0] to registers ldr r8, [ip, r3, lsl #2] ; load output sample pair from paintbuffer
ldr r8, [ip, r3, lsl #2] // load paintbuffer[0:1] = RIGHTCHANNEL:LEFTCHANNEL ; (left:right in memory -> right:left in register)
;; right channel (high half)
mul r5, r4, r1 ; scaledright = sfx[i] * (true_rvol << 16) -- bottom half is zero
qadd r7, r5, r8 ; right = scaledright + right (in high half of word)
bic r7, r7, sl ; zero bottom half of r7
// handle high half (right channel) first ;; left channel (low half)
mul r5, r4, r1 // SCALEDRIGHT = SFXI * (true_rvol << 16) -- bottom half is zero mul r5, r4, r0 ; scaledleft = sfx[i] * (true_rvol << 16)
mov r8, r8, lsl #16 ; extract original left channel from paintbuffer
qadd r8, r5, r8 ; left = scaledleft + left
// r7 holds right channel in high half (dirty bottom half) orr r7, r7, r8, lsr #16 ; combine right:left in r7
qadd r7, r5, r8 // RIGHTCHANORIG = SCALEDRIGHT + RIGHTCHANORIG (high half) str r7, [ip, r3, lsl #2] ; write right:left to output buffer
bic r7, r7, sl // zero bottom bits of r7
// trash r5, r6 and handle left channel
mul r5, r4, r0 // SCALEDLEFT = SFXI * (true_rvol << 16)
mov r8, r8, lsl #16 // extract original left channel from paintbuffer
// r8 holds left channel in high half with zero bottom half
qadd r8, r5, r8
// combine the two 16-bit samples in r7 as 32-bit [left:right]
// (use lsr to not sign-extend the lower half)
orr r7, r7, r8, lsr #16
str r7, [ip, r3, lsl #2] // write 32-bit to paintbuffer
subs r3, r3, #1 subs r3, r3, #1
bgt .loop // must use instead of bne because of the corner case count=1
bgt 1b ; must use bgt instead of bne in case count=1
ldmfd sp!, {r4, r5, r6, r7, r8, sl} ldmfd sp!, {r4, r5, r6, r7, r8, sl}
bx lr bx lr
#elif defined(__ARM_ARCH_6__) // ARMv6 with QADD16 (disabled) #elif defined(__ARM_ARCH_6__) ; ARMv6 with QADD16 (disabled)
SND_PaintChannelFrom8: SND_PaintChannelFrom8:
// r0: int true_lvol ;; r0: int true_lvol
// r1: int true_rvol ;; r1: int true_rvol
// r2: char *sfx ;; r2: char *sfx
// r3: int count ;; r3: int count
stmfd sp!, {r4, r5, r6, r7} stmfd sp!, {r4, r5, r6, r7}
ldr ip, =paintbuffer ldr ip, =paintbuffer
ldr ip, [ip] ldr ip, [ip] ; load paintbuffer address
sub r3, r3, #1 // we'll count backwards sub r3, r3, #1 ; we'll count backwards
.loop: 1:
ldrsb r4, [r2, r3] // load *sfx[i] -> r4 ldrsb r4, [r2, r3] ; load sfx[i] -> r4
ldr r7, [ip, r3, lsl #2] ; load old sample pair
// keep endianness in mind here mul r5, r4, r1 ; SCALEDRIGHT = SFXI * true_rvol
// buffer looks like [left_0, left_1, right_0, right_1] in memory mul r6, r4, r0 ; SCALEDLEFT = SFXI * true_rvol
// but it is loaded as [right1, right0, left1, left0] to registers
ldr r7, [ip, r3, lsl #2] // load paintbuffer[0:1] = RIGHTCHANNEL:LEFTCHANNEL
// handle high half (right channel) first orr r6, r6, r5, lsl #16 ; combine samples as 32-bit
mul r5, r4, r1 // SCALEDRIGHT = SFXI * true_rvol
mul r6, r4, r0 // SCALEDLEFT = SFXI * true_rvol
orr r6, r6, r5, lsl #16 qadd16 r6, r6, r7 ; parallel 16-bit add
qadd16 r6, r6, r7 str r6, [ip, r3, lsl #2] ; write 32-bit to paintbuffer
str r6, [ip, r3, lsl #2] // write 32-bit to paintbuffer
subs r3, r3, #1 subs r3, r3, #1
bne .loop bgt 1b
ldmfd sp!, {r4, r5, r6, r7} ldmfd sp!, {r4, r5, r6, r7}