SystemC自带example的cpu之Data Cache研习

        例子中并没有数据缓冲的体现，和指令缓冲一样，仅仅就是RAM的读写设计。上来先是对RAM内容进行初始化，然后就是根据输入的使能信号和读写地址，直接进行相应的操作了。

struct dcache : sc_module {
sc_in<signed>
datain;
// input data
sc_in<unsigned>
statein;
// input state bit MESI(=3210)
sc_in<bool>
cs;
// chip select
sc_in<bool>
we;
// write enable
sc_in<unsigned >
addr;
// address
sc_in<unsigned>
dest;
// write back to which register
sc_out<unsigned>
destout;
// write back to which register
sc_out<signed>
dataout;
// dataram data out
sc_out<bool>
out_valid;
// output valid
sc_out<unsigned>
stateout;
// state output
sc_in_clk
CLK;
// Parameter
unsigned *dmemory;
// data memory
unsigned *dsmemory;
// data state memory
unsigned *dtagmemory;
// tag memory
int wait_cycles;
// cycles # it takes to access dmemory
void init_param(int given_delay_cycles) {
wait_cycles = given_delay_cycles;
}
//Constructor
SC_CTOR(dcache) {
SC_CTHREAD(entry, CLK.pos());
// initialize instruction dmemory from external file
FILE *fp = fopen("dcache.img","r");
int size=0;
int i=0;
unsigned mem_word;
dmemory = new unsigned[4000];
dsmemory = new unsigned[4000];
dtagmemory = new unsigned[4000];
printf("** ALERT ** DCU: initialize Data Cachen");
while (fscanf(fp,"%x", &mem_word) != EOF) {
dmemory[size] = mem_word;
dsmemory[size] = 0;
dtagmemory[size] = size;
size++;
}
for (i=size; i<4000; i++) {
dtagmemory[i] = 0xdeadbeef;
dmemory[i] = 0xdeadbeef;
dsmemory[i] = 0;
}
}
// Process functionality in member function below
void entry();
};
void dcache::entry()
{
unsigned int	address;
// address to DataCache
unsigned int
dest_tmp = 0;
while (true) {
do { wait(); }
while ( !(cs == true) );
dest_tmp = dest.read();
address = addr.read();
if (we.read() == true) {
// Write operation
wait();
out_valid.write(false);
dmemory[address] = datain.read();
dsmemory[address] = statein.read();
dtagmemory[address] = addr.read();
wait();
}
else {
// Read operation
wait();
dataout.write(dmemory[address]);
stateout.write(dsmemory[address]);
destout.write(dest_tmp);
out_valid.write(true);
if (dsmemory[address] == 3) {
printf(" (M)");
} else if (dsmemory[address] == 2) {
printf(" (E)");
} else
if (dsmemory[address] == 1) {
printf(" (S)");
} else if (dsmemory[address] == 0) {
printf(" (I)");
} else
printf(" (X)");
wait();
out_valid.write(false);
wait();
}
}
} // end of entry function

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