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/**
* exception.c
*
* Exception handling code (part 2)
*/
#include <stdio.h>
#include <stdlib.h>
#include <psx.h>
#define DICR *((unsigned int*)0x1f8010f4)
#define IPENDING *((volatile unsigned int*)0x1f801070)
#define IMASK *((volatile unsigned int*)0x1f801074)
void __psxsdk_exception_manager();
void (*_EXC_vblank_handler)();
void (*_EXC_cdrom_handler)();
void (*_EXC_sio_handler)(unsigned char *data);
void (*_EXC_dma_handler)();
unsigned int _EXC_vblank_handler_set;
unsigned int _EXC_cdrom_handler_set;
unsigned int _EXC_sio_handler_set;
unsigned int _EXC_dma_handler_set;
volatile int __psxsdk_gpu_dma_finished;
void __psxsdk_real_exception_handler()
{
unsigned int Cause = get_cop0_register(COP0_CAUSE);
unsigned int Cause_excCode = (Cause >> 2) & 31;
unsigned int Cause_IP = (Cause >> 8) & 255;
unsigned int SR = get_cop0_register(COP0_SR);
unsigned int SR_IM = (SR >> 8) & 255;
int i;
/* unsigned int oldSR = SR;
unsigned int psxIP = IPENDING;
unsigned int psxIM = IMASK;
unsigned int sio_data;*/
if(Cause_excCode == 0) // interrupt generated the exception
{
/*for(i = 0; i < 8; i++)
{
if((Cause_IP & (1<<i)) && (SR_IM & (1<<i)))
{
SR ^= 1<<(i+8);
set_cop0_register(COP0_SR, SR);
switch(i)
{
case 2: // PSX Interrupt controller
// program_vblank_handler();
break;
}
}
}*/
if((Cause_IP & (1<<2)) && (SR_IM & (1<<2)))
{
Cause ^= 1<<10;
set_cop0_register(COP0_CAUSE, Cause);
//SR ^= 1<<10;
//set_cop0_register(COP0_SR, SR);
//while(IPENDING != 0)
{
for(i = 0; i < 11; i++)
{
if(IPENDING & (1<<i))
{
// printf("IP = %x\n", IPENDING);
// Very interesting, when reading joypad status the PCSXR emulator sets in IPENDING that IRQ7 is pending even
// if it is not enabled in IMASK! That is insane, but it can be easily worked around.
// So we are going to disable pending bits for IRQs in IPENDING in any case, even if the in IRQ at hand was
// not enabled in IMASK.
IPENDING ^= 1 << i;
if(IMASK & (1<<i))
{
// printf("IM = %x\n", IMASK);
switch(i)
{
case 0: // VBLANK
// if(!(GPU_CONTROL_PORT & (1<<0x1c)))
// GPU_CONTROL_PORT = 0x02000000;
// Execute the user-supplied VBlank handler.
if(_EXC_vblank_handler_set)
_EXC_vblank_handler();
break;
case 2:
/* if(_EXC_cdrom_handler_set)
_EXC_cdrom_handler();*/
break;
case 3: // DMA
// Execute the user-supplied DMA handler.
if(_EXC_dma_handler_set)
_EXC_dma_handler();
break;
case 8:
//while(!(SIO_STAT & 2))
//sio_data = SIO_RX_DATA;
//_EXC_sio_handler((unsigned char*)&sio_data);
// SIO_CTRL |= SIOCTRL_ACK;
break;
}
}
}
}
}
}
}
}
static void __psxsdk_dma_handler()
{
unsigned int s_dicr = DICR;
unsigned char irq = (s_dicr >> 24) & 127;
if(irq & (1<<2)) // GPU
__psxsdk_gpu_dma_finished = 1;
// Acknowledge
DICR = s_dicr;
// Waste some cycles, so that the acknowledgement is reported
// int x;
// for(x = 0; x < 1000; x++);
}
extern void _internal_cdromlib_callback();
void __PSX_Init_NoBios()
{
_EXC_vblank_handler = NULL;
_EXC_cdrom_handler = _internal_cdromlib_callback;
_EXC_dma_handler = __psxsdk_dma_handler;
_EXC_sio_handler = NULL;
_EXC_vblank_handler_set = 0;
_EXC_cdrom_handler_set = 0;
_EXC_dma_handler_set = 1;
_EXC_sio_handler_set = 0;
IMASK = 0; // Clear Mask
IPENDING = 0; // Clear pending interrupts
// Disable interrupts
set_cop0_register(COP0_SR, 0);
// Change exception vector to point to our exception manager
*((unsigned int*)0x80000080) = 0x08000000 | ((((unsigned int)__psxsdk_exception_manager)>>2) & 0x3FFFFFF);
*((unsigned int*)0x80000084) = 0;
// Enable interrupt generation, and interrupt 2 (PlayStation Interrupt Controller)
set_cop0_register(COP0_SR, (1<<10) | 1);
// Enable VBlank, CDROM and DMA IRQs (on PlayStation Interrupt Controller)
IMASK = 1 | /* CDROM */ /*4 |*/ 8;
// Set DMA channel priority
DPCR = 0x07654321;
// Enable DMA IRQ master, and IRQ generation for DMA channel 2 (GPU)
DICR = (1<<23) | (1<<(16+2));
// Setup variables
__psxsdk_gpu_dma_finished = 1;
}
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