emu48plus-mirror/source/EXTERNAL.C

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/*
* external.c
*
* This file is part of Emu48
*
* Copyright (C) 1995 Sebastien Carlier
*
*/
#include "pch.h"
#include "Emu48.h"
#include "ops.h"
#define SAMPLES_PER_SEC 44100 // sound sampling rate
//| 38G | 39G | 40G | 48SX | 48GX | 49G | Name
//#F0E4F #80F0F #80F0F #706D2 #80850 #80F0F =SFLAG53_56
// memory address for flags -53 to -56
// CdB for HP: add apples beep management
#define SFLAG53_56 ( (cCurrentRomType=='6') \
? 0xE0E4F \
: ( (cCurrentRomType=='A') \
? 0xF0E4F \
: ( (cCurrentRomType!='E' && cCurrentRomType!='X' && cCurrentRomType!='P' && cCurrentRomType!='2' && cCurrentRomType!='Q') \
? ( (cCurrentRomType=='S') \
? 0x706D2 \
: 0x80850 \
) \
: 0x80F0F \
) \
) \
)
VOID External(CHIPSET* w) // Beep patch
{
BYTE fbeep;
DWORD freq,dur;
freq = Npack(w->D,5); // frequency in Hz
dur = Npack(w->C,5); // duration in ms
Nread(&fbeep,SFLAG53_56,1); // fetch system flags -53 to -56
w->carry = TRUE; // setting of no beep
if (!(fbeep & 0x8) && freq) // bit -56 clear and frequency > 0 Hz
{
if (freq > 4400) freq = 4400; // high limit of HP (SX)
SoundBeep(freq,dur); // beeping
// estimate cpu cycles for beeping time (2MHz / 4MHz)
w->cycles += dur * ((cCurrentRomType=='S') ? 2000 : 4000);
// original routine return with...
w->P = 0; // P=0
w->intk = TRUE; // INTON
w->carry = FALSE; // RTNCC
}
w->pc = rstkpop();
return;
}
VOID RCKBp(CHIPSET* w) // ROM Check Beep patch
{
DWORD dw2F,dwCpuFreq;
DWORD freq,dur;
BYTE f,d;
f = w->C[1]; // f = freq ctl
d = w->C[0]; // d = duration ctl
if (cCurrentRomType == 'S') // Clarke chip with 48S ROM
{
// CPU strobe frequency @ RATE 14 = 1.97MHz
dwCpuFreq = ((14 + 1) * 524288) >> 2;
dw2F = f * 126 + 262; // F=f*63+131
}
else // York chip with 48G and later ROM
{
// CPU strobe frequency @ RATE 27 = 3.67MHz
// CPU strobe frequency @ RATE 29 = 3.93MHz
dwCpuFreq = ((27 + 1) * 524288) >> 2;
dw2F = f * 180 + 367; // F=f*90+183.5
}
freq = dwCpuFreq / dw2F;
dur = (dw2F * (256 - 16 * d)) * 1000 / 2 / dwCpuFreq;
if (freq > 4400) freq = 4400; // high limit of HP
SoundBeep(freq,dur); // beeping
// estimate cpu cycles for beeping time (2MHz / 4MHz)
w->cycles += dur * ((cCurrentRomType=='S') ? 2000 : 4000);
w->P = 0; // P=0
w->carry = FALSE; // RTNCC
w->pc = rstkpop();
return;
}