tumbledemerald-legacy/gflib/dma3_manager.c

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C
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2022-05-19 19:14:13 +02:00
#include "global.h"
#include "dma3.h"
#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
struct Dma3Request
{
const u8 *src;
u8 *dest;
u16 size;
u16 mode;
u32 value;
};
static struct Dma3Request sDma3Requests[MAX_DMA_REQUESTS];
static vbool8 sDma3ManagerLocked;
static u8 sDma3RequestCursor;
void ClearDma3Requests(void)
{
int i;
sDma3ManagerLocked = TRUE;
sDma3RequestCursor = 0;
for (i = 0; i < MAX_DMA_REQUESTS; i++)
{
sDma3Requests[i].size = 0;
sDma3Requests[i].src = NULL;
sDma3Requests[i].dest = NULL;
}
sDma3ManagerLocked = FALSE;
}
void ProcessDma3Requests(void)
{
u16 bytesTransferred;
if (sDma3ManagerLocked)
return;
bytesTransferred = 0;
// as long as there are DMA requests to process (unless size or vblank is an issue), do not exit
while (sDma3Requests[sDma3RequestCursor].size != 0)
{
bytesTransferred += sDma3Requests[sDma3RequestCursor].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 (sDma3Requests[sDma3RequestCursor].mode)
{
case DMA_REQUEST_COPY32: // regular 32-bit copy
Dma3CopyLarge32_(sDma3Requests[sDma3RequestCursor].src,
sDma3Requests[sDma3RequestCursor].dest,
sDma3Requests[sDma3RequestCursor].size);
break;
case DMA_REQUEST_FILL32: // repeat a single 32-bit value across RAM
Dma3FillLarge32_(sDma3Requests[sDma3RequestCursor].value,
sDma3Requests[sDma3RequestCursor].dest,
sDma3Requests[sDma3RequestCursor].size);
break;
case DMA_REQUEST_COPY16: // regular 16-bit copy
Dma3CopyLarge16_(sDma3Requests[sDma3RequestCursor].src,
sDma3Requests[sDma3RequestCursor].dest,
sDma3Requests[sDma3RequestCursor].size);
break;
case DMA_REQUEST_FILL16: // repeat a single 16-bit value across RAM
Dma3FillLarge16_(sDma3Requests[sDma3RequestCursor].value,
sDma3Requests[sDma3RequestCursor].dest,
sDma3Requests[sDma3RequestCursor].size);
break;
}
// Free the request
sDma3Requests[sDma3RequestCursor].src = NULL;
sDma3Requests[sDma3RequestCursor].dest = NULL;
sDma3Requests[sDma3RequestCursor].size = 0;
sDma3Requests[sDma3RequestCursor].mode = 0;
sDma3Requests[sDma3RequestCursor].value = 0;
sDma3RequestCursor++;
if (sDma3RequestCursor >= MAX_DMA_REQUESTS) // loop back to the first DMA request
sDma3RequestCursor = 0;
}
}
s16 RequestDma3Copy(const void *src, void *dest, u16 size, u8 mode)
{
int cursor;
int i = 0;
sDma3ManagerLocked = TRUE;
cursor = sDma3RequestCursor;
while (i < MAX_DMA_REQUESTS)
{
if (sDma3Requests[cursor].size == 0) // an empty request was found.
{
sDma3Requests[cursor].src = src;
sDma3Requests[cursor].dest = dest;
sDma3Requests[cursor].size = size;
if (mode == 1)
sDma3Requests[cursor].mode = DMA_REQUEST_COPY32;
else
sDma3Requests[cursor].mode = DMA_REQUEST_COPY16;
sDma3ManagerLocked = FALSE;
return cursor;
}
if (++cursor >= MAX_DMA_REQUESTS) // loop back to start.
cursor = 0;
i++;
}
sDma3ManagerLocked = 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 = sDma3RequestCursor;
sDma3ManagerLocked = TRUE;
while (i < MAX_DMA_REQUESTS)
{
if (sDma3Requests[cursor].size == 0) // an empty request was found.
{
sDma3Requests[cursor].dest = dest;
sDma3Requests[cursor].size = size;
sDma3Requests[cursor].mode = mode;
sDma3Requests[cursor].value = value;
if(mode == 1)
sDma3Requests[cursor].mode = DMA_REQUEST_FILL32;
else
sDma3Requests[cursor].mode = DMA_REQUEST_FILL16;
sDma3ManagerLocked = FALSE;
return cursor;
}
if (++cursor >= MAX_DMA_REQUESTS) // loop back to start.
cursor = 0;
i++;
}
sDma3ManagerLocked = FALSE;
return -1; // no free DMA request was found
}
s16 CheckForSpaceForDma3Request(s16 index)
{
int i = 0;
if (index == -1) // check if all requests are free
{
while (i < MAX_DMA_REQUESTS)
{
if (sDma3Requests[i].size != 0)
return -1;
i++;
}
return 0;
}
else // check the specified request
{
if (sDma3Requests[index].size != 0)
return -1;
return 0;
}
}