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#include "global.h"
#include "dma3.h"
// Maximum amount of data we will transfer in one operation
#define MAX_DMA_BLOCK_SIZE 0x1000
#define MAX_DMA_REQUESTS 128
#define DMA_REQUEST_COPY32 1
#define DMA_REQUEST_FILL32 2
#define DMA_REQUEST_COPY16 3
#define DMA_REQUEST_FILL16 4
IWRAM_DATA struct
{
const u8 *src;
u8 *dest;
u16 size;
u16 mode;
u32 value;
} gDma3Requests[MAX_DMA_REQUESTS];
static bool8 gDma3ManagerLocked;
static u8 gDma3RequestCursor;
void ClearDma3Requests(void)
{
int i;
gDma3ManagerLocked = TRUE;
gDma3RequestCursor = 0;
for (i = 0; i < MAX_DMA_REQUESTS; i++)
{
gDma3Requests[i].size = 0;
gDma3Requests[i].src = NULL;
gDma3Requests[i].dest = NULL;
}
gDma3ManagerLocked = FALSE;
}
#define Dma3CopyLarge_(src, dest, size, bit) \
{ \
const void *_src = src; \
void *_dest = dest; \
u32 _size = size; \
while (1) \
{ \
if (_size <= MAX_DMA_BLOCK_SIZE) \
{ \
DmaCopy##bit(3, _src, _dest, _size); \
break; \
} \
DmaCopy##bit(3, _src, _dest, MAX_DMA_BLOCK_SIZE); \
_src += MAX_DMA_BLOCK_SIZE; \
_dest += MAX_DMA_BLOCK_SIZE; \
_size -= MAX_DMA_BLOCK_SIZE; \
} \
}
#define Dma3CopyLarge16_(src, dest, size) Dma3CopyLarge_(src, dest, size, 16)
#define Dma3CopyLarge32_(src, dest, size) Dma3CopyLarge_(src, dest, size, 32)
#define Dma3FillLarge_(value, dest, size, bit) \
{ \
void *_dest = dest; \
u32 _size = size; \
while (1) \
{ \
if (_size <= MAX_DMA_BLOCK_SIZE) \
{ \
DmaFill##bit(3, value, _dest, _size); \
break; \
} \
DmaFill##bit(3, value, _dest, MAX_DMA_BLOCK_SIZE); \
_dest += MAX_DMA_BLOCK_SIZE; \
_size -= MAX_DMA_BLOCK_SIZE; \
} \
}
#define Dma3FillLarge16_(value, dest, size) Dma3FillLarge_(value, dest, size, 16)
#define Dma3FillLarge32_(value, dest, size) Dma3FillLarge_(value, dest, size, 32)
void ProcessDma3Requests(void)
{
u16 bytesTransferred;
if (gDma3ManagerLocked)
return;
bytesTransferred = 0;
// as long as there are DMA requests to process (unless size or vblank is an issue), do not exit
while (gDma3Requests[gDma3RequestCursor].size != 0)
{
bytesTransferred += gDma3Requests[gDma3RequestCursor].size;
if (bytesTransferred > 40 * 1024)
return; // don't transfer more than 40 KiB
if (*(u8 *)REG_ADDR_VCOUNT > 224)
return; // we're about to leave vblank, stop
switch (gDma3Requests[gDma3RequestCursor].mode)
{
case DMA_REQUEST_COPY32: // regular 32-bit copy
Dma3CopyLarge32_(gDma3Requests[gDma3RequestCursor].src,
gDma3Requests[gDma3RequestCursor].dest,
gDma3Requests[gDma3RequestCursor].size);
break;
case DMA_REQUEST_FILL32: // repeat a single 32-bit value across RAM
Dma3FillLarge32_(gDma3Requests[gDma3RequestCursor].value,
gDma3Requests[gDma3RequestCursor].dest,
gDma3Requests[gDma3RequestCursor].size);
break;
case DMA_REQUEST_COPY16: // regular 16-bit copy
Dma3CopyLarge16_(gDma3Requests[gDma3RequestCursor].src,
gDma3Requests[gDma3RequestCursor].dest,
gDma3Requests[gDma3RequestCursor].size);
break;
case DMA_REQUEST_FILL16: // repeat a single 16-bit value across RAM
Dma3FillLarge16_(gDma3Requests[gDma3RequestCursor].value,
gDma3Requests[gDma3RequestCursor].dest,
gDma3Requests[gDma3RequestCursor].size);
break;
}
// Free the request
gDma3Requests[gDma3RequestCursor].src = NULL;
gDma3Requests[gDma3RequestCursor].dest = NULL;
gDma3Requests[gDma3RequestCursor].size = 0;
gDma3Requests[gDma3RequestCursor].mode = 0;
gDma3Requests[gDma3RequestCursor].value = 0;
gDma3RequestCursor++;
if (gDma3RequestCursor >= MAX_DMA_REQUESTS) // loop back to the first DMA request
gDma3RequestCursor = 0;
}
}
s16 RequestDma3Copy(const void *src, void *dest, u16 size, u8 mode)
{
int cursor;
int i = 0;
gDma3ManagerLocked = TRUE;
cursor = gDma3RequestCursor;
while (i < MAX_DMA_REQUESTS)
{
if (gDma3Requests[cursor].size == 0) // an empty request was found.
{
gDma3Requests[cursor].src = src;
gDma3Requests[cursor].dest = dest;
gDma3Requests[cursor].size = size;
if (mode == 1)
gDma3Requests[cursor].mode = DMA_REQUEST_COPY32;
else
gDma3Requests[cursor].mode = DMA_REQUEST_COPY16;
gDma3ManagerLocked = FALSE;
return cursor;
}
if (++cursor >= MAX_DMA_REQUESTS) // loop back to start.
cursor = 0;
i++;
}
gDma3ManagerLocked = FALSE;
return -1; // no free DMA request was found
}
s16 RequestDma3Fill(s32 value, void *dest, u16 size, u8 mode)
{
int cursor;
int i = 0;
cursor = gDma3RequestCursor;
gDma3ManagerLocked = TRUE;
while (i < MAX_DMA_REQUESTS)
{
if (gDma3Requests[cursor].size == 0) // an empty request was found.
{
gDma3Requests[cursor].dest = dest;
gDma3Requests[cursor].size = size;
gDma3Requests[cursor].mode = mode;
gDma3Requests[cursor].value = value;
if(mode == 1)
gDma3Requests[cursor].mode = DMA_REQUEST_FILL32;
else
gDma3Requests[cursor].mode = DMA_REQUEST_FILL16;
gDma3ManagerLocked = FALSE;
return cursor;
}
if (++cursor >= MAX_DMA_REQUESTS) // loop back to start.
cursor = 0;
i++;
}
gDma3ManagerLocked = FALSE;
return -1; // no free DMA request was found
}
int CheckForSpaceForDma3Request(s16 index)
{
int i = 0;
if (index == -1) // check if all requests are free
{
while (i < MAX_DMA_REQUESTS)
{
if (gDma3Requests[i].size != 0)
return -1;
i++;
}
return 0;
}
else // check the specified request
{
if (gDma3Requests[index].size != 0)
return -1;
return 0;
}
}
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