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/* This file is an implementation of the functions
defined in mips_mem.h. It is designed to be
linked against something which needs an implementation
of a RAM device following that memory mapping
interface.
*/
#include "mips_mem.h"
#include <stdio.h>
#include <stdlib.h>
struct mips_mem_provider
{
uint32_t length;
uint8_t *data;
};
extern "C" mips_mem_h mips_mem_create_ram(
uint32_t cbMem //!< Total number of bytes of ram
){
if(cbMem>0x20000000){
return 0; // No more than 512MB of RAM
}
uint8_t *data=(uint8_t*)malloc(cbMem);
if(data==0)
return 0;
struct mips_mem_provider *mem=(struct mips_mem_provider*)malloc(sizeof(struct mips_mem_provider));
if(mem==0){
free(data);
return 0;
}
mem->length=cbMem;
mem->data=data;
return mem;
}
static mips_error mips_mem_read_write(
bool write,
mips_mem_h mem,
uint32_t address,
uint32_t length,
uint8_t *dataOut
)
{
if(mem==0){
return mips_ErrorInvalidHandle;
}
if( (length!=1) && (length!=2) && (length!=4) ){
return mips_ExceptionInvalidLength;
}
if(0 != (address % length) ){
return mips_ExceptionInvalidAlignment;
}
if(((address+length) > mem->length) || (address > (UINT32_MAX - length))){ // A subtle bug here, maybe?
return mips_ExceptionInvalidAddress;
}
if(write){
for(unsigned i=0; i<length; i++){
mem->data[address+i]=dataOut[i];
}
}else{
for(unsigned i=0; i<length; i++){
dataOut[i]=mem->data[address+i];
}
}
return mips_Success;
}
mips_error mips_mem_read(
mips_mem_h mem, //!< Handle to target memory
uint32_t address, //!< Byte address to start transaction at
uint32_t length, //!< Number of bytes to transfer
uint8_t *dataOut //!< Receives the target bytes
)
{
return mips_mem_read_write(
false, // we want to read
mem,
address,
length,
dataOut
);
}
mips_error mips_mem_write(
mips_mem_h mem, //! Handle to target memory
uint32_t address, //! Byte address to start transaction at
uint32_t length, //! Number of bytes to transfer
const uint8_t *dataIn //! Receives the target bytes
)
{
return mips_mem_read_write(
true, // we want to write
mem,
address,
length,
(uint8_t*)dataIn
);
}
void mips_mem_free(mips_mem_h mem)
{
if(mem){
free(mem->data);
mem->data=0;
free(mem);
}
}
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