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#include "global.h"
#include "agb_sram.h"
// this should be in .bss
extern /*static*/ u16 verifySramFast_Work[80]; // buffer to hold code of VerifySramFast_Core
extern /*static*/ u16 readSramFast_Work[64]; // buffer to hold code of ReadSramFast_Core
u32 (*VerifySramFast)(const u8 *src, u8 *dest, u32 size); // pointer to verifySramFast_Work
void (*ReadSramFast)(const u8 *src, u8 *dest, u32 size); // pointer to readSramFast_Work
void ReadSramFast_Core(const u8 *src, u8 *dest, u32 size)
{
REG_WAITCNT = (REG_WAITCNT & ~3) | 3;
while (--size != -1)
*dest++ = *src++;
}
void WriteSramFast(const u8 *src, u8 *dest, u32 size)
{
REG_WAITCNT = (REG_WAITCNT & ~3) | 3;
while (--size != -1)
*dest++ = *src++;
}
u32 VerifySramFast_Core(const u8 *src, u8 *dest, u32 size)
{
REG_WAITCNT = (REG_WAITCNT & ~3) | 3;
while (--size != -1)
{
if (*dest++ != *src++)
return (u32)(dest - 1);
}
return 0;
}
void SetSramFastFunc(void)
{
u16 *src;
u16 *dest;
u16 size;
src = (u16 *)ReadSramFast_Core;
// clear the least significant bit so that we get the actual start address of the function
src = (u16 *)((uintptr_t)src ^ 1); // NOTE: In Fire Emblem 8, this is '& ~1' instead of '^ 1'.
dest = readSramFast_Work;
// get the size of the function by subtracting the address of the next function
size = ((uintptr_t)WriteSramFast - (uintptr_t)ReadSramFast_Core) / 2;
// copy the function into the WRAM buffer
while (size != 0)
{
*dest++ = *src++;
size--;
}
// add 1 to the address of the buffer so that we stay in THUMB mode when bx-ing to the address
ReadSramFast = (void *)((uintptr_t)readSramFast_Work + 1);
src = (u16 *)VerifySramFast_Core;
// clear the least significant bit so that we get the actual start address of the function
src = (u16 *)((uintptr_t)src ^ 1); // NOTE: In Fire Emblem 8, this is '& ~1' instead of '^ 1'.
dest = verifySramFast_Work;
// get the size of the function by subtracting the address of the next function
size = ((uintptr_t)SetSramFastFunc - (uintptr_t)VerifySramFast_Core) / 2;
// copy the function into the WRAM buffer
while (size != 0)
{
*dest++ = *src++;
size--;
}
// add 1 to the address of the buffer so that we stay in THUMB mode when bx-ing to the address
VerifySramFast = (void *)((uintptr_t)verifySramFast_Work + 1);
REG_WAITCNT = (REG_WAITCNT & ~3) | 3;
}
u32 WriteAndVerifySramFast(const u8 *src, u8 *dest, u32 size)
{
u8 i;
u32 errorAddr;
// try writing and verifying the data 3 times
for (i = 0; i < 3; i++)
{
WriteSramFast(src, dest, size);
errorAddr = VerifySramFast(src, dest, size);
if (errorAddr == 0)
break;
}
return errorAddr;
}
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