From 24b79880d085c23e127ffcf851d6dd55455513f9 Mon Sep 17 00:00:00 2001
From: b1ackmai1er <difficultylevelhigh@gmail.com>
Date: Sun, 3 May 2020 23:05:08 +0800
Subject: [PATCH] Update ay38910.asm

code optimizations
---
 Source/HBIOS/ay38910.asm | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/Source/HBIOS/ay38910.asm b/Source/HBIOS/ay38910.asm
index 6e109b4e..624bb82f 100644
--- a/Source/HBIOS/ay38910.asm
+++ b/Source/HBIOS/ay38910.asm
@@ -58,7 +58,7 @@ AY_IDAT	.EQU	0			; NO INSTANCE DATA ASSOCIATED WITH THIS DEVICE
 ;
 ;	DEVICE CAPABILITIES AND CONFIGURATION
 ;
-SBCV2004	.EQU	0		; USE SBC-V2-004 HALF CLOCK DIVIDER
+SBCV2004	.EQU	0			; USE SBC-V2-004 HALF CLOCK DIVIDER
 ;
 AY_TONECNT	.EQU	3		; COUNT NUMBER OF TONE CHANNELS
 AY_NOISECNT	.EQU	1		; COUNT NUMBER OF NOISE CHANNELS
@@ -129,11 +129,13 @@ AY_INIT:
 ;======================================================================
 ;
 AY_SETV:
+	PUSH	BC
 	LD	B,AY_TONECNT		; NUMBER OF CHANNELS
 	LD	D,AY_R8AVOL		; BASE REGISTER FOR VOLUME
 AY_SV:	CALL	AY_WRTPSG		; CYCLING THROUGH ALL CHANNELS
 	INC	D
 	DJNZ	AY_SV
+	POP	BC
 	RET
 ;
 ;======================================================================
@@ -219,8 +221,9 @@ AY_NOTE:
 	JR	NC, AY_NOTE1		; INCOMING HL DOES NOT MAP INTO AY3NOTETBL
 ;
 	ADD	HL, DE			; RESTORE HL
-	EX	DE,HL
-	LD	HL, AY3NOTETBL		; HL = AY3NOTETBL + HL
+;	EX	DE,HL
+;	LD	HL, AY3NOTETBL		; HL = AY3NOTETBL + HL
+	LD	DE, AY3NOTETBL		; HL = AY3NOTETBL + HL
 	ADD	HL, DE
 ;
 	LD	A, (HL)			; RETRIEVE PERIOD COUNT FROM AY3NOTETBL
@@ -288,11 +291,13 @@ AY_PLAY:
 	AUDTRACE_CR
 ;
 	INC	HL			; NEXT BYTE
-	LD	E,(HL)
-	SRL	E			; MAP THE VOLUME
-	SRL	E			; FROM 00-FF		
-	SRL	E			; TO 00-0F
-	SRL	E
+	LD	A,(HL)			; PENDING VOLUME
+	RRCA				; MAP THE VOLUME
+	RRCA				; FROM 00-FF
+	RRCA				; TO 00-0F
+	RRCA
+	AND	$0F
+	LD	E,A
 	CALL	AY_WRTPSG		; SET VOL (E) IN CHANNEL REG (D)
 ;
 	POP	DE			; RECALL CHANNEL