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ym2612 ARM, bug fixing and small optimizations

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This commit is contained in:
kub 2020-04-02 20:33:56 +02:00
parent 86198e034b
commit e8204ab27b
1 changed files with 16 additions and 9 deletions
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25
pico/sound/ym2612_arm.S
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@ -15,6 +15,9 @@
#include "../arm_features.h"
@ very simple adaption YM2612 output rate to sample rate (~1M cycles @44100)
//#define INTERPOL
.equiv SLOT1, 0
.equiv SLOT2, 2
.equiv SLOT3, 1
@ -42,10 +45,14 @@
@ r5=slot, r1=eg_cnt, trashes: r0,r2,r3
@ writes output to routp, but only if vol_out changes
.macro update_eg_phase_slot slot
#if defined(INTERPOL)
ldrh r0, [r5,#0x34] @ vol_out
#endif
ldrb r2, [r5,#0x17] @ state
add r3, r5, #0x1c
#if defined(INTERPOL)
strh r0, [r5,#0x36] @ vol_ipol
#endif
tst r2, r2
beq 0f @ EG_OFF
@ -59,11 +66,11 @@
bne 0f @ no volume change
mov r3, r1, lsr r0
ldrb r0, [r5,#0x30] @ ssg
and r3, r3, #7
add r3, r3, r3, lsl #1
mov r3, r2, lsr r3
and r3, r3, #7 @ eg_inc_val shift, may be 0
ldrb r0, [r5,#0x30] @ ssg
ldrb r2, [r5,#0x17] @ state
tst r0, #0x08 @ ssg enabled?
@ -124,8 +131,8 @@
b 11f
9: @ SSG-EG mode
cmp r2, #4 @ EG_ATT
ldrh r0, [r5,#0x1a] @ volume, unsigned (0-1023)
cmp r2, #4 @ EG_ATT
beq 4f
cmp r0, #0x200 @ if ( volume < 0x200 )
@ -170,9 +177,9 @@
strgeb r3, [r5,#0x17] @ state
10: @ finish
strh r0, [r5,#0x1a] @ volume
ldrb r2, [r5,#0x30] @ ssg
ldrb r3, [r5,#0x17] @ state
strh r0, [r5,#0x1a] @ volume
cmp r2, #0x0c @ if ( ssg&0x04 && state > EG_REL )
cmpge r3, #EG_REL+1
rsbge r0, r0, #0x200 @ volume = (0x200-volume) & MAX_ATT
@ -206,10 +213,10 @@
.macro update_ssg_eg
ldrh r0, [r5,#0x30] @ ssg+ssgn
ldrb r2, [r5,#0x17] @ state
and r3, r0, #0x08
cmp r3, #0x08 @ ssg enabled &&
ldrh r3, [r5,#0x1a] @ volume
cmpge r2, #EG_REL+1 @ state > EG_REL &&
tst r0, #0x08 @ ssg enabled &&
beq 9f
cmp r2, #EG_REL+1 @ state > EG_REL &&
cmpge r3, #0x200 @ volume >= 0x200?
blt 9f
@ -222,7 +229,7 @@
orrne r0, r0, #0x400 @ ssgn = 4
strneh r0, [r5,#0x30]
eor r0, r0, #0x4 @ if ( !(ssg&0x04 )
eor r0, r0, #0x4 @ if ( !(ssg&0x04) )
tst r0, #0x4
cmpne r2, #EG_ATT @ if ( state != EG_ATT )
movne r3, #0x400
@ -747,7 +754,7 @@ eg_done:
beq crl_loop
@ output interpolation
#if 0
#if 0 // too expensive on slow platforms
@ basic interpolator, interpolate in middle region, else use closer value
mov r3, r8, lsr #EG_SH @ eg_timer, [0..3<<EG_SH) after loop
cmp r3, #(EG_TIMER_OVERFLOW>>EG_SH)/2
@ -780,7 +787,7 @@ eg_done:
mov r7, r7, lsl #16
orr r7, r7, r0
ror r7, r7, #16
#elif 0
#elif defined(INTERPOL)
@ super-basic... just take value closest to sample point
mov r3, r8, lsr #EG_SH-1 @ eg_timer, [0..3<<EG_SH) after loop
cmp r3, #(EG_TIMER_OVERFLOW>>EG_SH)