mirror of
https://github.com/AppleWin/AppleWin.git
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8a433b6e0d
. Change: Added support for SSC receive IRQ (eg. Z-Link) . Fix: [Bug #7231] AppleWin installed in path with spaces Internal: . Modified operation of interrupt assert/deassert
791 lines
20 KiB
C++
791 lines
20 KiB
C++
/***************************************************************************
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ay8910.c
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Emulation of the AY-3-8910 / YM2149 sound chip.
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Based on various code snippets by Ville Hallik, Michael Cuddy,
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Tatsuyuki Satoh, Fabrice Frances, Nicola Salmoria.
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***************************************************************************/
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//
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// From mame.txt (http://www.mame.net/readme.html)
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//
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// VI. Reuse of Source Code
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// --------------------------
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// This chapter might not apply to specific portions of MAME (e.g. CPU
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// emulators) which bear different copyright notices.
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// The source code cannot be used in a commercial product without the written
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// authorization of the authors. Use in non-commercial products is allowed, and
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// indeed encouraged. If you use portions of the MAME source code in your
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// program, however, you must make the full source code freely available as
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// well.
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// Usage of the _information_ contained in the source code is free for any use.
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// However, given the amount of time and energy it took to collect this
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// information, if you find new information we would appreciate if you made it
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// freely available as well.
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//
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#include <windows.h>
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#include <stdio.h>
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#include <crtdbg.h>
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#include "ay8910.h"
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#include "Common.h"
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#include "Structs.h"
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#include "Applewin.h" // For g_fh
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#include "Mockingboard.h" // For g_uTimer1IrqCount
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///////////////////////////////////////////////////////////
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// typedefs & dummy funcs to allow MAME code to compile:
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typedef UINT8 (*mem_read_handler)(UINT32);
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typedef void (*mem_write_handler)(UINT32, UINT8);
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static void logerror(char* psz, ...)
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{
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}
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static unsigned short activecpu_get_pc()
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{
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return 0;
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}
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//
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///////////////////////////////////////////////////////////
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#define MAX_OUTPUT 0x7fff
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// See AY8910_set_clock() for definition of STEP
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#define STEP 0x8000
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static int num = 0, ym_num = 0;
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struct AY8910
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{
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int Channel;
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int SampleRate;
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mem_read_handler PortAread;
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mem_read_handler PortBread;
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mem_write_handler PortAwrite;
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mem_write_handler PortBwrite;
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int register_latch;
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unsigned char Regs[16];
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int lastEnable;
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unsigned int UpdateStep;
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int PeriodA,PeriodB,PeriodC,PeriodN,PeriodE;
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int CountA,CountB,CountC,CountN,CountE;
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unsigned int VolA,VolB,VolC,VolE;
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unsigned char EnvelopeA,EnvelopeB,EnvelopeC;
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unsigned char OutputA,OutputB,OutputC,OutputN;
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signed char CountEnv;
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unsigned char Hold,Alternate,Attack,Holding;
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int RNG;
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unsigned int VolTable[32];
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};
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/* register id's */
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#define AY_AFINE (0)
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#define AY_ACOARSE (1)
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#define AY_BFINE (2)
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#define AY_BCOARSE (3)
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#define AY_CFINE (4)
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#define AY_CCOARSE (5)
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#define AY_NOISEPER (6)
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#define AY_ENABLE (7)
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#define AY_AVOL (8)
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#define AY_BVOL (9)
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#define AY_CVOL (10)
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#define AY_EFINE (11)
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#define AY_ECOARSE (12)
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#define AY_ESHAPE (13)
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#define AY_PORTA (14)
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#define AY_PORTB (15)
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static struct AY8910 AYPSG[MAX_8910]; /* array of PSG's */
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static bool g_bAYReset = false; // Doing AY8910_reset()
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//-----------------------------------------------------------------------------
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//#define LOG_AY8910
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#ifdef LOG_AY8910
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static void LogAY8910(int n, int r, UINT uFreq)
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{
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// TO DO: Determine freq from 6522 timer
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if ((g_fh == NULL) || g_bAYReset)
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return;
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static UINT nCnt = 0;
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const UINT nNumAYs = 4; // 1..4
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if((r == 0))
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{
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if(nCnt == 0)
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{
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fprintf(g_fh, "Time : ");
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for(UINT i=0; i<nNumAYs; i++)
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fprintf(g_fh, "APer BPer CPer NP EN AV BV CV ");
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fprintf(g_fh, "\n");
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}
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fprintf(g_fh, "%02d.%02d: ", g_uTimer1IrqCount/uFreq, g_uTimer1IrqCount%uFreq);
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for(int j=0; j<n*(3*5+5*3+1); j++)
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fprintf(g_fh, " ");
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UINT i=n;
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{
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UCHAR* pAYRegs = &AYPSG[i].Regs[0];
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fprintf(g_fh, "%04X ", *(USHORT*)&pAYRegs[AY_AFINE]);
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fprintf(g_fh, "%04X ", *(USHORT*)&pAYRegs[AY_BFINE]);
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fprintf(g_fh, "%04X ", *(USHORT*)&pAYRegs[AY_CFINE]);
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fprintf(g_fh, "%02X ", pAYRegs[AY_NOISEPER]);
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fprintf(g_fh, "%02X ", pAYRegs[AY_ENABLE]);
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fprintf(g_fh, "%02X ", pAYRegs[AY_AVOL]);
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fprintf(g_fh, "%02X ", pAYRegs[AY_BVOL]);
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fprintf(g_fh, "%02X ", pAYRegs[AY_CVOL]);
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}
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fprintf(g_fh, "\n");
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nCnt++;
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}
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}
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#endif
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//-----------------------------------------------------------------------------
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void _AYWriteReg(int n, int r, int v)
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{
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struct AY8910 *PSG = &AYPSG[n];
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int old;
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PSG->Regs[r] = v;
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#ifdef LOG_AY8910
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LogAY8910(n, r, 60);
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#endif
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/* A note about the period of tones, noise and envelope: for speed reasons,*/
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/* we count down from the period to 0, but careful studies of the chip */
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/* output prove that it instead counts up from 0 until the counter becomes */
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/* greater or equal to the period. This is an important difference when the*/
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/* program is rapidly changing the period to modulate the sound. */
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/* To compensate for the difference, when the period is changed we adjust */
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/* our internal counter. */
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/* Also, note that period = 0 is the same as period = 1. This is mentioned */
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/* in the YM2203 data sheets. However, this does NOT apply to the Envelope */
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/* period. In that case, period = 0 is half as period = 1. */
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switch( r )
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{
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case AY_AFINE:
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case AY_ACOARSE:
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PSG->Regs[AY_ACOARSE] &= 0x0f;
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old = PSG->PeriodA;
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PSG->PeriodA = (PSG->Regs[AY_AFINE] + 256 * PSG->Regs[AY_ACOARSE]) * PSG->UpdateStep;
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if (PSG->PeriodA == 0) PSG->PeriodA = PSG->UpdateStep;
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PSG->CountA += PSG->PeriodA - old;
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if (PSG->CountA <= 0) PSG->CountA = 1;
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break;
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case AY_BFINE:
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case AY_BCOARSE:
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PSG->Regs[AY_BCOARSE] &= 0x0f;
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old = PSG->PeriodB;
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PSG->PeriodB = (PSG->Regs[AY_BFINE] + 256 * PSG->Regs[AY_BCOARSE]) * PSG->UpdateStep;
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if (PSG->PeriodB == 0) PSG->PeriodB = PSG->UpdateStep;
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PSG->CountB += PSG->PeriodB - old;
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if (PSG->CountB <= 0) PSG->CountB = 1;
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break;
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case AY_CFINE:
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case AY_CCOARSE:
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PSG->Regs[AY_CCOARSE] &= 0x0f;
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old = PSG->PeriodC;
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PSG->PeriodC = (PSG->Regs[AY_CFINE] + 256 * PSG->Regs[AY_CCOARSE]) * PSG->UpdateStep;
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if (PSG->PeriodC == 0) PSG->PeriodC = PSG->UpdateStep;
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PSG->CountC += PSG->PeriodC - old;
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if (PSG->CountC <= 0) PSG->CountC = 1;
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break;
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case AY_NOISEPER:
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PSG->Regs[AY_NOISEPER] &= 0x1f;
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old = PSG->PeriodN;
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PSG->PeriodN = PSG->Regs[AY_NOISEPER] * PSG->UpdateStep;
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if (PSG->PeriodN == 0) PSG->PeriodN = PSG->UpdateStep;
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PSG->CountN += PSG->PeriodN - old;
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if (PSG->CountN <= 0) PSG->CountN = 1;
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break;
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case AY_ENABLE:
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if ((PSG->lastEnable == -1) ||
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((PSG->lastEnable & 0x40) != (PSG->Regs[AY_ENABLE] & 0x40)))
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{
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/* write out 0xff if port set to input */
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if (PSG->PortAwrite)
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(*PSG->PortAwrite)(0, (UINT8) ((PSG->Regs[AY_ENABLE] & 0x40) ? PSG->Regs[AY_PORTA] : 0xff)); // [TC: UINT8 cast]
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}
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if ((PSG->lastEnable == -1) ||
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((PSG->lastEnable & 0x80) != (PSG->Regs[AY_ENABLE] & 0x80)))
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{
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/* write out 0xff if port set to input */
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if (PSG->PortBwrite)
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(*PSG->PortBwrite)(0, (UINT8) ((PSG->Regs[AY_ENABLE] & 0x80) ? PSG->Regs[AY_PORTB] : 0xff)); // [TC: UINT8 cast]
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}
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PSG->lastEnable = PSG->Regs[AY_ENABLE];
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break;
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case AY_AVOL:
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PSG->Regs[AY_AVOL] &= 0x1f;
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PSG->EnvelopeA = PSG->Regs[AY_AVOL] & 0x10;
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PSG->VolA = PSG->EnvelopeA ? PSG->VolE : PSG->VolTable[PSG->Regs[AY_AVOL] ? PSG->Regs[AY_AVOL]*2+1 : 0];
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break;
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case AY_BVOL:
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PSG->Regs[AY_BVOL] &= 0x1f;
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PSG->EnvelopeB = PSG->Regs[AY_BVOL] & 0x10;
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PSG->VolB = PSG->EnvelopeB ? PSG->VolE : PSG->VolTable[PSG->Regs[AY_BVOL] ? PSG->Regs[AY_BVOL]*2+1 : 0];
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break;
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case AY_CVOL:
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PSG->Regs[AY_CVOL] &= 0x1f;
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PSG->EnvelopeC = PSG->Regs[AY_CVOL] & 0x10;
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PSG->VolC = PSG->EnvelopeC ? PSG->VolE : PSG->VolTable[PSG->Regs[AY_CVOL] ? PSG->Regs[AY_CVOL]*2+1 : 0];
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break;
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case AY_EFINE:
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case AY_ECOARSE:
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// _ASSERT((PSG->Regs[AY_EFINE] == 0) && (PSG->Regs[AY_ECOARSE] == 0));
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old = PSG->PeriodE;
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PSG->PeriodE = ((PSG->Regs[AY_EFINE] + 256 * PSG->Regs[AY_ECOARSE])) * PSG->UpdateStep;
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if (PSG->PeriodE == 0) PSG->PeriodE = PSG->UpdateStep / 2;
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PSG->CountE += PSG->PeriodE - old;
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if (PSG->CountE <= 0) PSG->CountE = 1;
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break;
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case AY_ESHAPE:
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// _ASSERT(PSG->Regs[AY_ESHAPE] == 0);
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/* envelope shapes:
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C AtAlH
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0 0 x x \___
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0 1 x x /___
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1 0 0 0 \\\\
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1 0 0 1 \___
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1 0 1 0 \/\/
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___
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1 0 1 1 \
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1 1 0 0 ////
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___
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1 1 0 1 /
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1 1 1 0 /\/\
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1 1 1 1 /___
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The envelope counter on the AY-3-8910 has 16 steps. On the YM2149 it
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has twice the steps, happening twice as fast. Since the end result is
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just a smoother curve, we always use the YM2149 behaviour.
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*/
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PSG->Regs[AY_ESHAPE] &= 0x0f;
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PSG->Attack = (PSG->Regs[AY_ESHAPE] & 0x04) ? 0x1f : 0x00;
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if ((PSG->Regs[AY_ESHAPE] & 0x08) == 0)
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{
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/* if Continue = 0, map the shape to the equivalent one which has Continue = 1 */
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PSG->Hold = 1;
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PSG->Alternate = PSG->Attack;
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}
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else
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{
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PSG->Hold = PSG->Regs[AY_ESHAPE] & 0x01;
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PSG->Alternate = PSG->Regs[AY_ESHAPE] & 0x02;
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}
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PSG->CountE = PSG->PeriodE;
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PSG->CountEnv = 0x1f;
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PSG->Holding = 0;
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PSG->VolE = PSG->VolTable[PSG->CountEnv ^ PSG->Attack];
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if (PSG->EnvelopeA) PSG->VolA = PSG->VolE;
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if (PSG->EnvelopeB) PSG->VolB = PSG->VolE;
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if (PSG->EnvelopeC) PSG->VolC = PSG->VolE;
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break;
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case AY_PORTA:
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if (PSG->Regs[AY_ENABLE] & 0x40)
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{
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if (PSG->PortAwrite)
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(*PSG->PortAwrite)(0, PSG->Regs[AY_PORTA]);
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else
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logerror("PC %04x: warning - write %02x to 8910 #%d Port A\n",activecpu_get_pc(),PSG->Regs[AY_PORTA],n);
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}
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else
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{
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logerror("warning: write to 8910 #%d Port A set as input - ignored\n",n);
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}
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break;
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case AY_PORTB:
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if (PSG->Regs[AY_ENABLE] & 0x80)
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{
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if (PSG->PortBwrite)
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(*PSG->PortBwrite)(0, PSG->Regs[AY_PORTB]);
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else
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logerror("PC %04x: warning - write %02x to 8910 #%d Port B\n",activecpu_get_pc(),PSG->Regs[AY_PORTB],n);
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}
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else
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{
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logerror("warning: write to 8910 #%d Port B set as input - ignored\n",n);
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}
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break;
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}
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}
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// /length/ is the number of samples we require
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// NB. This should be called at twice the 6522 IRQ rate or (eg) 60Hz if no IRQ.
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void AY8910Update(int chip,INT16 **buffer,int length) // [TC: Removed static]
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{
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struct AY8910 *PSG = &AYPSG[chip];
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INT16 *buf1,*buf2,*buf3;
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int outn;
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buf1 = buffer[0];
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buf2 = buffer[1];
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buf3 = buffer[2];
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/* The 8910 has three outputs, each output is the mix of one of the three */
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/* tone generators and of the (single) noise generator. The two are mixed */
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/* BEFORE going into the DAC. The formula to mix each channel is: */
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/* (ToneOn | ToneDisable) & (NoiseOn | NoiseDisable). */
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/* Note that this means that if both tone and noise are disabled, the output */
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/* is 1, not 0, and can be modulated changing the volume. */
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/* If the channels are disabled, set their output to 1, and increase the */
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/* counter, if necessary, so they will not be inverted during this update. */
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/* Setting the output to 1 is necessary because a disabled channel is locked */
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/* into the ON state (see above); and it has no effect if the volume is 0. */
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/* If the volume is 0, increase the counter, but don't touch the output. */
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if (PSG->Regs[AY_ENABLE] & 0x01)
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{
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if (PSG->CountA <= length*STEP) PSG->CountA += length*STEP;
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PSG->OutputA = 1;
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}
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else if (PSG->Regs[AY_AVOL] == 0)
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{
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/* note that I do count += length, NOT count = length + 1. You might think */
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/* it's the same since the volume is 0, but doing the latter could cause */
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/* interferencies when the program is rapidly modulating the volume. */
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if (PSG->CountA <= length*STEP) PSG->CountA += length*STEP;
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}
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if (PSG->Regs[AY_ENABLE] & 0x02)
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{
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if (PSG->CountB <= length*STEP) PSG->CountB += length*STEP;
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PSG->OutputB = 1;
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}
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else if (PSG->Regs[AY_BVOL] == 0)
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{
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if (PSG->CountB <= length*STEP) PSG->CountB += length*STEP;
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}
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if (PSG->Regs[AY_ENABLE] & 0x04)
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{
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if (PSG->CountC <= length*STEP) PSG->CountC += length*STEP;
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PSG->OutputC = 1;
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}
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else if (PSG->Regs[AY_CVOL] == 0)
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{
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if (PSG->CountC <= length*STEP) PSG->CountC += length*STEP;
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}
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/* for the noise channel we must not touch OutputN - it's also not necessary */
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/* since we use outn. */
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if ((PSG->Regs[AY_ENABLE] & 0x38) == 0x38) /* all off */
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if (PSG->CountN <= length*STEP) PSG->CountN += length*STEP;
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outn = (PSG->OutputN | PSG->Regs[AY_ENABLE]);
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/* buffering loop */
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while (length)
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{
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int vola,volb,volc;
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int left;
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/* vola, volb and volc keep track of how long each square wave stays */
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/* in the 1 position during the sample period. */
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vola = volb = volc = 0;
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left = STEP;
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do
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{
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int nextevent;
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if (PSG->CountN < left) nextevent = PSG->CountN;
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else nextevent = left;
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if (outn & 0x08)
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{
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if (PSG->OutputA) vola += PSG->CountA;
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PSG->CountA -= nextevent;
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/* PeriodA is the half period of the square wave. Here, in each */
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/* loop I add PeriodA twice, so that at the end of the loop the */
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/* square wave is in the same status (0 or 1) it was at the start. */
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/* vola is also incremented by PeriodA, since the wave has been 1 */
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/* exactly half of the time, regardless of the initial position. */
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/* If we exit the loop in the middle, OutputA has to be inverted */
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/* and vola incremented only if the exit status of the square */
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/* wave is 1. */
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while (PSG->CountA <= 0)
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{
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PSG->CountA += PSG->PeriodA;
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if (PSG->CountA > 0)
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{
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PSG->OutputA ^= 1;
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if (PSG->OutputA) vola += PSG->PeriodA;
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break;
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}
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PSG->CountA += PSG->PeriodA;
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vola += PSG->PeriodA;
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}
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if (PSG->OutputA) vola -= PSG->CountA;
|
|
}
|
|
else
|
|
{
|
|
PSG->CountA -= nextevent;
|
|
while (PSG->CountA <= 0)
|
|
{
|
|
PSG->CountA += PSG->PeriodA;
|
|
if (PSG->CountA > 0)
|
|
{
|
|
PSG->OutputA ^= 1;
|
|
break;
|
|
}
|
|
PSG->CountA += PSG->PeriodA;
|
|
}
|
|
}
|
|
|
|
if (outn & 0x10)
|
|
{
|
|
if (PSG->OutputB) volb += PSG->CountB;
|
|
PSG->CountB -= nextevent;
|
|
while (PSG->CountB <= 0)
|
|
{
|
|
PSG->CountB += PSG->PeriodB;
|
|
if (PSG->CountB > 0)
|
|
{
|
|
PSG->OutputB ^= 1;
|
|
if (PSG->OutputB) volb += PSG->PeriodB;
|
|
break;
|
|
}
|
|
PSG->CountB += PSG->PeriodB;
|
|
volb += PSG->PeriodB;
|
|
}
|
|
if (PSG->OutputB) volb -= PSG->CountB;
|
|
}
|
|
else
|
|
{
|
|
PSG->CountB -= nextevent;
|
|
while (PSG->CountB <= 0)
|
|
{
|
|
PSG->CountB += PSG->PeriodB;
|
|
if (PSG->CountB > 0)
|
|
{
|
|
PSG->OutputB ^= 1;
|
|
break;
|
|
}
|
|
PSG->CountB += PSG->PeriodB;
|
|
}
|
|
}
|
|
|
|
if (outn & 0x20)
|
|
{
|
|
if (PSG->OutputC) volc += PSG->CountC;
|
|
PSG->CountC -= nextevent;
|
|
while (PSG->CountC <= 0)
|
|
{
|
|
PSG->CountC += PSG->PeriodC;
|
|
if (PSG->CountC > 0)
|
|
{
|
|
PSG->OutputC ^= 1;
|
|
if (PSG->OutputC) volc += PSG->PeriodC;
|
|
break;
|
|
}
|
|
PSG->CountC += PSG->PeriodC;
|
|
volc += PSG->PeriodC;
|
|
}
|
|
if (PSG->OutputC) volc -= PSG->CountC;
|
|
}
|
|
else
|
|
{
|
|
PSG->CountC -= nextevent;
|
|
while (PSG->CountC <= 0)
|
|
{
|
|
PSG->CountC += PSG->PeriodC;
|
|
if (PSG->CountC > 0)
|
|
{
|
|
PSG->OutputC ^= 1;
|
|
break;
|
|
}
|
|
PSG->CountC += PSG->PeriodC;
|
|
}
|
|
}
|
|
|
|
PSG->CountN -= nextevent;
|
|
if (PSG->CountN <= 0)
|
|
{
|
|
/* Is noise output going to change? */
|
|
if ((PSG->RNG + 1) & 2) /* (bit0^bit1)? */
|
|
{
|
|
PSG->OutputN = ~PSG->OutputN;
|
|
outn = (PSG->OutputN | PSG->Regs[AY_ENABLE]);
|
|
}
|
|
|
|
/* The Random Number Generator of the 8910 is a 17-bit shift */
|
|
/* register. The input to the shift register is bit0 XOR bit3 */
|
|
/* (bit0 is the output). This was verified on AY-3-8910 and YM2149 chips. */
|
|
|
|
/* The following is a fast way to compute bit17 = bit0^bit3. */
|
|
/* Instead of doing all the logic operations, we only check */
|
|
/* bit0, relying on the fact that after three shifts of the */
|
|
/* register, what now is bit3 will become bit0, and will */
|
|
/* invert, if necessary, bit14, which previously was bit17. */
|
|
if (PSG->RNG & 1) PSG->RNG ^= 0x24000; /* This version is called the "Galois configuration". */
|
|
PSG->RNG >>= 1;
|
|
PSG->CountN += PSG->PeriodN;
|
|
}
|
|
|
|
left -= nextevent;
|
|
} while (left > 0);
|
|
|
|
/* update envelope */
|
|
if (PSG->Holding == 0)
|
|
{
|
|
PSG->CountE -= STEP;
|
|
if (PSG->CountE <= 0)
|
|
{
|
|
do
|
|
{
|
|
PSG->CountEnv--;
|
|
PSG->CountE += PSG->PeriodE;
|
|
} while (PSG->CountE <= 0);
|
|
|
|
/* check envelope current position */
|
|
if (PSG->CountEnv < 0)
|
|
{
|
|
if (PSG->Hold)
|
|
{
|
|
if (PSG->Alternate)
|
|
PSG->Attack ^= 0x1f;
|
|
PSG->Holding = 1;
|
|
PSG->CountEnv = 0;
|
|
}
|
|
else
|
|
{
|
|
/* if CountEnv has looped an odd number of times (usually 1), */
|
|
/* invert the output. */
|
|
if (PSG->Alternate && (PSG->CountEnv & 0x20))
|
|
PSG->Attack ^= 0x1f;
|
|
|
|
PSG->CountEnv &= 0x1f;
|
|
}
|
|
}
|
|
|
|
PSG->VolE = PSG->VolTable[PSG->CountEnv ^ PSG->Attack];
|
|
/* reload volume */
|
|
if (PSG->EnvelopeA) PSG->VolA = PSG->VolE;
|
|
if (PSG->EnvelopeB) PSG->VolB = PSG->VolE;
|
|
if (PSG->EnvelopeC) PSG->VolC = PSG->VolE;
|
|
}
|
|
}
|
|
|
|
#if 0
|
|
*(buf1++) = (vola * PSG->VolA) / STEP;
|
|
*(buf2++) = (volb * PSG->VolB) / STEP;
|
|
*(buf3++) = (volc * PSG->VolC) / STEP;
|
|
#else
|
|
// Output PCM wave [-32768...32767] instead of MAME's voltage level [0...32767]
|
|
// - This allows for better s/w mixing
|
|
|
|
if(PSG->VolA)
|
|
{
|
|
if(vola)
|
|
*(buf1++) = (vola * PSG->VolA) / STEP;
|
|
else
|
|
*(buf1++) = - (int) PSG->VolA;
|
|
}
|
|
else
|
|
{
|
|
*(buf1++) = 0;
|
|
}
|
|
|
|
//
|
|
|
|
if(PSG->VolB)
|
|
{
|
|
if(volb)
|
|
*(buf2++) = (volb * PSG->VolB) / STEP;
|
|
else
|
|
*(buf2++) = - (int) PSG->VolB;
|
|
}
|
|
else
|
|
{
|
|
*(buf2++) = 0;
|
|
}
|
|
|
|
//
|
|
|
|
if(PSG->VolC)
|
|
{
|
|
if(volc)
|
|
*(buf3++) = (volc * PSG->VolC) / STEP;
|
|
else
|
|
*(buf3++) = - (int) PSG->VolC;
|
|
}
|
|
else
|
|
{
|
|
*(buf3++) = 0;
|
|
}
|
|
#endif
|
|
|
|
length--;
|
|
}
|
|
}
|
|
|
|
|
|
static void AY8910_set_clock(int chip,int clock)
|
|
{
|
|
struct AY8910 *PSG = &AYPSG[chip];
|
|
|
|
/* the step clock for the tone and noise generators is the chip clock */
|
|
/* divided by 8; for the envelope generator of the AY-3-8910, it is half */
|
|
/* that much (clock/16), but the envelope of the YM2149 goes twice as */
|
|
/* fast, therefore again clock/8. */
|
|
/* Here we calculate the number of steps which happen during one sample */
|
|
/* at the given sample rate. No. of events = sample rate / (clock/8). */
|
|
/* STEP is a multiplier used to turn the fraction into a fixed point */
|
|
/* number. */
|
|
PSG->UpdateStep = (unsigned int) (((double)STEP * PSG->SampleRate * 8 + clock/2) / clock); // [TC: unsigned int cast]
|
|
}
|
|
|
|
|
|
static void build_mixer_table(int chip)
|
|
{
|
|
struct AY8910 *PSG = &AYPSG[chip];
|
|
int i;
|
|
double out;
|
|
|
|
|
|
/* calculate the volume->voltage conversion table */
|
|
/* The AY-3-8910 has 16 levels, in a logarithmic scale (3dB per step) */
|
|
/* The YM2149 still has 16 levels for the tone generators, but 32 for */
|
|
/* the envelope generator (1.5dB per step). */
|
|
out = MAX_OUTPUT;
|
|
for (i = 31;i > 0;i--)
|
|
{
|
|
PSG->VolTable[i] = (unsigned int) (out + 0.5); /* round to nearest */ // [TC: unsigned int cast]
|
|
|
|
out /= 1.188502227; /* = 10 ^ (1.5/20) = 1.5dB */
|
|
}
|
|
PSG->VolTable[0] = 0;
|
|
}
|
|
|
|
|
|
#if 0
|
|
void ay8910_write_ym(int chip, int addr, int data)
|
|
{
|
|
struct AY8910 *PSG = &AYPSG[chip];
|
|
|
|
// if (addr & 1)
|
|
// { /* Data port */
|
|
// int r = PSG->register_latch;
|
|
int r = addr;
|
|
|
|
if (r > 15) return;
|
|
if (r < 14)
|
|
{
|
|
if (r == AY_ESHAPE || PSG->Regs[r] != data)
|
|
{
|
|
/* update the output buffer before changing the register */
|
|
// stream_update(PSG->Channel,0);
|
|
AY8910Update(chip, INT16 **buffer, int length)
|
|
}
|
|
}
|
|
|
|
_AYWriteReg(PSG,r,data);
|
|
}
|
|
// else
|
|
// { /* Register port */
|
|
// PSG->register_latch = data & 0x0f;
|
|
// }
|
|
}
|
|
#endif
|
|
|
|
|
|
void AY8910_reset(int chip)
|
|
{
|
|
g_bAYReset = true;
|
|
|
|
int i;
|
|
struct AY8910 *PSG = &AYPSG[chip];
|
|
|
|
PSG->register_latch = 0;
|
|
PSG->RNG = 1;
|
|
PSG->OutputA = 0;
|
|
PSG->OutputB = 0;
|
|
PSG->OutputC = 0;
|
|
PSG->OutputN = 0xff;
|
|
PSG->lastEnable = -1; /* force a write */
|
|
for (i = 0;i < AY_PORTA;i++)
|
|
_AYWriteReg(chip,i,0); /* AYWriteReg() uses the timer system; we cannot */
|
|
/* call it at this time because the timer system */
|
|
/* has not been initialized. */
|
|
|
|
g_bAYReset = false;
|
|
}
|
|
|
|
//-------------------------------------
|
|
|
|
void AY8910_InitAll(int nClock, int nSampleRate)
|
|
{
|
|
for(int nChip=0; nChip<MAX_8910; nChip++)
|
|
{
|
|
struct AY8910 *PSG = &AYPSG[nChip];
|
|
|
|
memset(PSG,0,sizeof(struct AY8910));
|
|
PSG->SampleRate = nSampleRate;
|
|
|
|
PSG->PortAread = NULL;
|
|
PSG->PortBread = NULL;
|
|
PSG->PortAwrite = NULL;
|
|
PSG->PortBwrite = NULL;
|
|
|
|
AY8910_set_clock(nChip, nClock);
|
|
|
|
build_mixer_table(nChip);
|
|
}
|
|
}
|
|
|
|
//-------------------------------------
|
|
|
|
void AY8910_InitClock(int nClock)
|
|
{
|
|
for(int nChip=0; nChip<MAX_8910; nChip++)
|
|
{
|
|
AY8910_set_clock(nChip, nClock);
|
|
}
|
|
}
|
|
|
|
//-------------------------------------
|
|
|
|
BYTE* AY8910_GetRegsPtr(UINT nAyNum)
|
|
{
|
|
if(nAyNum >= MAX_8910)
|
|
return NULL;
|
|
|
|
return &AYPSG[nAyNum].Regs[0];
|
|
}
|