in cores/snes/spc7110emu.cpp [348:642]
void SPC7110::mmio_write(unsigned addr, uint8 data) {
addr &= 0xffff;
switch(addr) {
//==================
//decompression unit
//==================
case 0x4801: r4801 = data; break;
case 0x4802: r4802 = data; break;
case 0x4803: r4803 = data; break;
case 0x4804: r4804 = data; break;
case 0x4805: r4805 = data; break;
case 0x4806: {
r4806 = data;
unsigned table = (r4801 + (r4802 << 8) + (r4803 << 16));
unsigned index = (r4804 << 2);
//unsigned length = (r4809 + (r480a << 8));
unsigned addr = datarom_addr(table + index);
unsigned mode = (memory_cartrom_read(addr + 0));
unsigned offset = (memory_cartrom_read(addr + 1) << 16)
+ (memory_cartrom_read(addr + 2) << 8)
+ (memory_cartrom_read(addr + 3) << 0);
decomp.init(mode, offset, (r4805 + (r4806 << 8)) << mode);
r480c = 0x80;
} break;
case 0x4807: r4807 = data; break;
case 0x4808: r4808 = data; break;
case 0x4809: r4809 = data; break;
case 0x480a: r480a = data; break;
case 0x480b: r480b = data; break;
//==============
//data port unit
//==============
case 0x4811: r4811 = data; r481x |= 0x01; break;
case 0x4812: r4812 = data; r481x |= 0x02; break;
case 0x4813: r4813 = data; r481x |= 0x04; break;
case 0x4814: {
r4814 = data;
r4814_latch = true;
if(!r4815_latch) break;
if(!(r4818 & 2)) break;
if(r4818 & 0x10) break;
if((r4818 & 0x60) == 0x20) {
unsigned increment = data_adjust() & 0xff;
if(r4818 & 8) increment = (int8)increment; //8-bit sign extend
set_data_pointer(data_pointer() + increment);
} else if((r4818 & 0x60) == 0x40) {
unsigned increment = data_adjust();
if(r4818 & 8) increment = (int16)increment; //16-bit sign extend
set_data_pointer(data_pointer() + increment);
}
} break;
case 0x4815: {
r4815 = data;
r4815_latch = true;
if(!r4814_latch) break;
if(!(r4818 & 2)) break;
if(r4818 & 0x10) break;
if((r4818 & 0x60) == 0x20) {
unsigned increment = data_adjust() & 0xff;
if(r4818 & 8) increment = (int8)increment; //8-bit sign extend
set_data_pointer(data_pointer() + increment);
} else if((r4818 & 0x60) == 0x40) {
unsigned increment = data_adjust();
if(r4818 & 8) increment = (int16)increment; //16-bit sign extend
set_data_pointer(data_pointer() + increment);
}
} break;
case 0x4816: r4816 = data; break;
case 0x4817: r4817 = data; break;
case 0x4818: {
if(r481x != 0x07) break;
r4818 = data;
r4814_latch = r4815_latch = false;
} break;
//=========
//math unit
//=========
case 0x4820: r4820 = data; break;
case 0x4821: r4821 = data; break;
case 0x4822: r4822 = data; break;
case 0x4823: r4823 = data; break;
case 0x4824: r4824 = data; break;
case 0x4825: {
r4825 = data;
if(r482e & 1) {
//signed 16-bit x 16-bit multiplication
int16 r0 = (int16)(r4824 + (r4825 << 8));
int16 r1 = (int16)(r4820 + (r4821 << 8));
signed result = r0 * r1;
r4828 = result;
r4829 = result >> 8;
r482a = result >> 16;
r482b = result >> 24;
} else {
//unsigned 16-bit x 16-bit multiplication
uint16 r0 = (uint16)(r4824 + (r4825 << 8));
uint16 r1 = (uint16)(r4820 + (r4821 << 8));
unsigned result = r0 * r1;
r4828 = result;
r4829 = result >> 8;
r482a = result >> 16;
r482b = result >> 24;
}
r482f = 0x80;
} break;
case 0x4826: r4826 = data; break;
case 0x4827: {
r4827 = data;
if(r482e & 1) {
//signed 32-bit x 16-bit division
int32 dividend = (int32)(r4820 + (r4821 << 8) + (r4822 << 16) + (r4823 << 24));
int16 divisor = (int16)(r4826 + (r4827 << 8));
int32 quotient;
int16 remainder;
if(divisor) {
quotient = (int32)(dividend / divisor);
remainder = (int32)(dividend % divisor);
} else {
//illegal division by zero
quotient = 0;
remainder = dividend & 0xffff;
}
r4828 = quotient;
r4829 = quotient >> 8;
r482a = quotient >> 16;
r482b = quotient >> 24;
r482c = remainder;
r482d = remainder >> 8;
} else {
//unsigned 32-bit x 16-bit division
uint32 dividend = (uint32)(r4820 + (r4821 << 8) + (r4822 << 16) + (r4823 << 24));
uint16 divisor = (uint16)(r4826 + (r4827 << 8));
uint32 quotient;
uint16 remainder;
if(divisor) {
quotient = (uint32)(dividend / divisor);
remainder = (uint16)(dividend % divisor);
} else {
//illegal division by zero
quotient = 0;
remainder = dividend & 0xffff;
}
r4828 = quotient;
r4829 = quotient >> 8;
r482a = quotient >> 16;
r482b = quotient >> 24;
r482c = remainder;
r482d = remainder >> 8;
}
r482f = 0x80;
} break;
case 0x482e: {
//reset math unit
r4820 = r4821 = r4822 = r4823 = 0;
r4824 = r4825 = r4826 = r4827 = 0;
r4828 = r4829 = r482a = r482b = 0;
r482c = r482d = 0;
r482e = data;
} break;
//===================
//memory mapping unit
//===================
case 0x4830: r4830 = data; break;
case 0x4831: {
r4831 = data;
dx_offset = datarom_addr((data & 7) * 0x100000);
} break;
case 0x4832: {
r4832 = data;
ex_offset = datarom_addr((data & 7) * 0x100000);
} break;
case 0x4833: {
r4833 = data;
fx_offset = datarom_addr((data & 7) * 0x100000);
} break;
case 0x4834: r4834 = data; break;
//====================
//real-time clock unit
//====================
case 0x4840: {
r4840 = data;
if(!(r4840 & 1)) {
//disable RTC
rtc_state = RTCS_Inactive;
update_time();
} else {
//enable RTC
r4842 = 0x80;
rtc_state = RTCS_ModeSelect;
}
} break;
case 0x4841: {
r4841 = data;
switch(rtc_state) {
case RTCS_ModeSelect: {
if(data == RTCM_Linear || data == RTCM_Indexed) {
r4842 = 0x80;
rtc_state = RTCS_IndexSelect;
rtc_mode = (RTC_Mode)data;
rtc_index = 0;
}
} break;
case RTCS_IndexSelect: {
r4842 = 0x80;
rtc_index = data & 15;
if(rtc_mode == RTCM_Linear) rtc_state = RTCS_Write;
} break;
case RTCS_Write: {
r4842 = 0x80;
//control register 0
if(rtc_index == 13) {
//increment second counter
if(data & 2) update_time(+1);
//round minute counter
if(data & 8) {
update_time();
unsigned second = memory_cartrtc_read( 0) + memory_cartrtc_read( 1) * 10;
//clear seconds
memory_cartrtc_write(0, 0);
memory_cartrtc_write(1, 0);
if(second >= 30) update_time(+60);
}
}
//control register 2
if(rtc_index == 15) {
//disable timer and clear second counter
if((data & 1) && !(memory_cartrtc_read(15) & 1)) {
update_time();
//clear seconds
memory_cartrtc_write(0, 0);
memory_cartrtc_write(1, 0);
}
//disable timer
if((data & 2) && !(memory_cartrtc_read(15) & 2)) {
update_time();
}
}
memory_cartrtc_write(rtc_index, data & 15);
rtc_index = (rtc_index + 1) & 15;
} break;
case RTCS_Inactive: {
} break;
} //switch(rtc_state)
} break;
}
}