A minimized RISCV C compiler that supports a subset of C operations, including functions and recursions, arithmetic operators, multi-dimensional arrays, and flow control statements.
Some Caveats
- Definition must be at the top of each function
- Use
MAINinstead ofmainas program entry point
- Dijkstra (Single Source Shortest Path)
int G[5][5];
int d[5];
void build_graph(){
G[0][0]=0; G[0][1]=2; G[0][2]=9999; G[0][3]=6; G[0][4]=9999;
G[1][0]=2; G[1][1]=0; G[1][2]=3; G[1][3]=8; G[1][4]=5;
G[2][0]=9999; G[2][1]=3; G[2][2]=0; G[2][3]=9999; G[2][4]=7;
G[3][0]=6; G[3][1]=8; G[3][2]=9999; G[3][3]=0; G[3][4]=9;
G[4][0]=9999; G[4][1]=5; G[4][2]=7; G[4][3]=9; G[4][4]=0;
}
void Dijkstra(){
int parent[5];
int visited[5];
int i,j;
int a,w;
for(i=0;i<5;i=i+1){
d[i]=9999;
visited[i]=0;
}
d[0]=0;
parent[0]=0;
for(i=0;i<5;i=i+1){
a=-1;
w=9999;
for(j=0;j<5;j=j+1){
if((visited[j]==0)&&(d[j]<w)){
a=j;
w=d[j];
}
}
visited[a]=1;
for(j=0;j<5;j=j+1){
if((visited[j]==0)&&(d[a]+G[a][j]<d[j])){
d[j]=d[a]+G[a][j];
parent[j]=a;
}
}
}
}
int MAIN(){
int i;
build_graph();
Dijkstra();
write("Single-Source Shortest Path:\n");
for(i=0;i<5;i=i+1){
write("0-->");
write(i);
write(": cost=");
write(d[i]);
write("\n");
}
}more example is given at folder testcases
Source code
-> Lexical Analysis: Use Flex to parse source code to token stream (lexer3.l, define the Context Free Grammar (CFG) of the C--)
-> Syntax Analysis: Use Bison to build Abstract Syntax Tree (AST) from token stream (parser.y)
-> Semantic Analysis: Analyze AST's semantics and check for errors (semanticAnalysis.c)
-> Code Generation: Generate assembly code from AST (codegen.c)
-> Convert the assembly file to object file with riscv64-linux-gnu-gcc compiler
-> Run it on a RISCV64 simulator (we use qemu-riscv64 on CSIE workstation)