From: kub <derkub@gmail.com>
Date: Sun, 26 Jan 2020 19:12:18 +0000 (+0100)
Subject: audio fixes for overdrive demo
X-Git-Tag: v2.00~798
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7aab47685971b17e42719a7f876a6f469032406a;p=picodrive.git

audio fixes for overdrive demo
---

diff --git a/cpu/cz80/cz80.c b/cpu/cz80/cz80.c
index 6b9afcde..51abc40f 100644
--- a/cpu/cz80/cz80.c
+++ b/cpu/cz80/cz80.c
@@ -278,7 +278,8 @@ Cz80_Check_Interrupt:
 				CPU->ICount -= CPU->ExtraCycles;
 				CPU->ExtraCycles = 0;
 			}
-			goto Cz80_Exec;
+			if (!CPU->HaltState)
+				goto Cz80_Exec;
 		}
 	}
 	else CPU->ICount = 0;
diff --git a/cpu/cz80/cz80_op.c b/cpu/cz80/cz80_op.c
index 5d623caf..317e9587 100644
--- a/cpu/cz80/cz80_op.c
+++ b/cpu/cz80/cz80_op.c
@@ -687,7 +687,6 @@ OP_CCF:
 	OP(0x76):   // HALT
 OP_HALT:
 		CPU->HaltState = 1;
-//		CPU->ICount = 0;
 		goto Cz80_Check_Interrupt;
 
 	OP(0xf3):   // DI
diff --git a/pico/memory.c b/pico/memory.c
index 1d9b9135..d61491c1 100644
--- a/pico/memory.c
+++ b/pico/memory.c
@@ -733,8 +733,10 @@ static void PicoWrite8_vdp(u32 a, u32 d)
 
 static void PicoWrite16_vdp(u32 a, u32 d)
 {
-  if ((a & 0x00f9) == 0x0010) // PSG Sound
+  if ((a & 0x00f9) == 0x0010) { // PSG Sound
     psg_write_68k(d);
+    return;
+  }
   if ((a & 0x00e0) == 0x0000) {
     PicoVideoWrite(a, d);
     return;
@@ -898,10 +900,10 @@ void ym2612_sync_timers(int z80_cycles, int mode_old, int mode_new)
   int xcycles = z80_cycles << 8;
 
   /* check for overflows */
-  if ((mode_old & 4) && xcycles > Pico.t.timer_a_next_oflow)
+  if ((mode_old & 4) && xcycles >= Pico.t.timer_a_next_oflow)
     ym2612.OPN.ST.status |= 1;
 
-  if ((mode_old & 8) && xcycles > Pico.t.timer_b_next_oflow)
+  if ((mode_old & 8) && xcycles >= Pico.t.timer_b_next_oflow)
     ym2612.OPN.ST.status |= 2;
 
   /* update timer a */
diff --git a/pico/pico_int.h b/pico/pico_int.h
index 58d3da88..70bfa710 100644
--- a/pico/pico_int.h
+++ b/pico/pico_int.h
@@ -822,10 +822,10 @@ void ym2612_pack_state(void);
 void ym2612_unpack_state(void);
 
 #define TIMER_NO_OFLOW 0x70000000
-// tA =   72 * (1024 - NA) / M
-#define TIMER_A_TICK_ZCYCLES  17203
-// tB = 1152 * (256 - NA) / M
-#define TIMER_B_TICK_ZCYCLES 262800 // 275251 broken, see Dai Makaimura
+// tA =   72 * (1024 - NA) / M, with M = mclock/2 -> tick = 72 * 2/mclock
+#define TIMER_A_TICK_ZCYCLES  17203 // zcycles = Q8*tick*zclock = Q8*77*2*7/15
+// tB = 1152 * (256 - NA) / M,
+#define TIMER_B_TICK_ZCYCLES 275251 // zcycles = Q8*1152*2*7/15
 
 #define timers_cycle() \
   if (Pico.t.timer_a_next_oflow > 0 && Pico.t.timer_a_next_oflow < TIMER_NO_OFLOW) \
@@ -837,7 +837,8 @@ void ym2612_unpack_state(void);
 #define timers_reset() \
   Pico.t.timer_a_next_oflow = Pico.t.timer_b_next_oflow = TIMER_NO_OFLOW; \
   Pico.t.timer_a_step = TIMER_A_TICK_ZCYCLES * 1024; \
-  Pico.t.timer_b_step = TIMER_B_TICK_ZCYCLES * 256;
+  Pico.t.timer_b_step = TIMER_B_TICK_ZCYCLES * 256; \
+  ym2612.OPN.ST.status &= ~3;
 
 
 // videoport.c
diff --git a/pico/sound/ym2612_arm.S b/pico/sound/ym2612_arm.S
index 4cb92850..e3ec370d 100644
--- a/pico/sound/ym2612_arm.S
+++ b/pico/sound/ym2612_arm.S
@@ -206,8 +206,9 @@
 .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
-    cmp     r0, #0x08                     @ ssg enabled &&
     cmpge   r2, #EG_REL+1                 @   state > EG_REL &&
     cmpge   r3, #0x200                    @   volume >= 0x200?
     blt     9f