1. Chapter 3 : Combination and Sequential Circuits Modeling

2. SC_MODULE SC_MODULE (module_name) {
// declarations of ports : input, output and inout
// Declarations of signals used in inter-process
// Communication
// Process method declarations
// Other (non-process) methods
// Child module instantiation pointer declarations
// Data variable declarations
SC_CTOR (module_name) {
//Child module instantiations and interconnections
SC_METHOD (process_method_name);
// Sensitivity list for process
SC_THREAD (process_method_name);

3. Combination Logic : Single Process
SC_MODULE (mac) {
sc_in<int> a, b, c;
sc_out<int> sum;
void proc_mac() { sum = a * b + c;};
SC_CTOR(mac) {
SC_METHOD(proc_mac)
sensitive << a << b << c; } };

4. Combination Logic Multiple Processes
SC_MODULE (mult_procs) {
Sc_int<bool> source;
Sc_out<bool> drain;
Sc_signal<bool> connect1, connect2;
void mult_procs_1() { connect1 = !source;);
void mult_procs_2() { connect2 = !connect;};
void mult_procs_3() { drain = !connect2;};
SC_CTOR (mult_procs) {
SC_METHOD (mult_procs_1);
sensitvie << source;
SC_METHOD (mult_procs_2);
sensitvie << connect1;
SC_METHOD (mult_procs_3);
sensitvie << connect2; } };

5. Sequential Logic Example
SC_MODULE (count4) {
//sc_in_clk  sc_in<bool>
sc_in_clk clk;
sc_in<bool> rst;
sc_out<int> cout;
int curValue;
void proc_mac() {
curValue = rst ? 0 : curValue + 1;
cout = curValue;};
SC_CTOR(mac) {
SC_METHOD(proc_mac)
sensitive_pos << clk << rst; //async reset
sensitive_pos << clk; //sync reset } };

6. Port Read and Write Issues
Code
SC_MODULE (xor) {
sc_in<sc_uint<4> > bre, sty;
sc_out<sc_uint<4> > tap;
void proc_xor() { tap = bre ^ sty;};
SC_CTOR (xor) {
SC_METHOD (proc_xor);
sensitive << bre << sty; } };
Compiler error
error C2678: 二元運算子 '^' : 找不到使用左方運算元型別 'sc_in<T>' 的運算子 (或是沒有可接受的轉換) with [ T=sc_dt::sc_uint<4> ]

7. Port Read and Write Issues (cont.)
Code
SC_MODULE (xor) {
sc_in<sc_uint<4> > bre, sty;
sc_out<sc_uint<4> > tap;
void proc_xor() { tap = bre.read() ^ sty.read();};
tap.write(bre.read() ^ sty.read());
SC_CTOR (xor) {
SC_METHOD (proc_xor);
sensitive << bre << sty; } };
Suggestion
Explicitly use port’s read and write method

8. Process Function Call No hierarchy Sensitivity List
Processes can’t call other processes directly
Sensitivity List

9. Process : SC_METHOD vs SC_THREAD
void full_adder::proc_full_adder() {
sum = a ^ b ^ carry;
co = (a & b) | (b & carry) | (carry & a); }
SC_THREAD
while (true) {
wait();

10. Process : SC_THREAD example
void blah::proc() {
while (true) {
if (mem_ready) {
tdata.range(7,0) = data8.read();
wait();
tdata.range(15,8) = data8.read();
tdata.range(23,16) = data8.read(); …. } …

11. Process : wait and wait_until
No argument
Process will be reactivated when certain variables, specified in sensitivity list, changes
Wait_until()
Need argument(s)
Prcoess will be reactivated when expression is true
Example
// now wait for ready signal from memory
// controller
wait_until(mem_ready.delayed() == true);