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#include "../copyright"
#include "seta.h"
#include "memmap.h"
ST018_Regs ST018;
uint8_t S9xGetST018(uint32_t Address)
{
uint8_t t = 0; // Initialise to some value for the compiler
uint16_t address = (uint16_t) Address & 0xFFFF;
// these roles may be flipped
// op output
if (address == 0x3804)
{
if (ST018.out_count)
{
t = (uint8_t) ST018.output [ST018.out_index];
ST018.out_index++;
if (ST018.out_count == ST018.out_index)
ST018.out_count = 0;
}
else
t = 0x81;
}
else if (address == 0x3800) // status register
t = ST018.status;
return t;
}
void S9xSetST018(uint8_t Byte, uint32_t Address)
{
uint16_t address = (uint16_t) Address & 0xFFFF;
static bool reset = false;
if (!reset) // bootup values
{
ST018.waiting4command = true;
ST018.part_command = 0;
reset = true;
}
Memory.SRAM[address] = Byte;
ST018.status = 0x00; // default status for now
if (address == 0x3804) // op data goes through this address
{
if (ST018.waiting4command && ST018.part_command == 2) // check for new commands: 3 bytes length
{
ST018.waiting4command = false;
ST018.command <<= 8;
ST018.command |= Byte;
ST018.in_index = 0;
ST018.out_index = 0;
ST018.part_command = 0; // 3-byte commands
ST018.pass = 0; // data streams into the chip
switch (ST018.command & 0xFFFFFF)
{
case 0x0100:
case 0xFF00:
ST018.in_count = 0;
break;
default:
ST018.waiting4command = true;
break;
}
}
else if (ST018.waiting4command) // 3-byte commands
{
ST018.part_command++;
ST018.command <<= 8;
ST018.command |= Byte;
}
}
else if (address == 0x3802) // extra parameters
{
ST018.parameters[ST018.in_index] = Byte;
ST018.in_index++;
}
if (ST018.in_count == ST018.in_index) // Actually execute the command
{
ST018.waiting4command = true;
ST018.in_index = 0;
ST018.out_index = 0;
switch (ST018.command)
{
case 0x0100:
case 0xFF00: // hardware check?
ST018.waiting4command = false;
ST018.pass++;
if (ST018.pass == 1)
{
ST018.in_count = 1;
ST018.out_count = 2;
// Overload's research
ST018.output[0x00] = 0x81;
ST018.output[0x01] = 0x81;
}
else
{
ST018.out_count = 3;
ST018.output[0x02] = 0x81;
// done processing requests
if (ST018.pass == 3)
ST018.waiting4command = true;
}
break;
}
}
}
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