Some optimizations

nrj.c

@@ -1,18 +1,19 @@
-/* Build with: cc -Os -o nrj nrj.c */
+/*
+ * NRJ (NOR and Reference Jump) OISC ANSI C emulator by Luxferre
+ * Public domain
+ * Build with: cc -Os -o nrj nrj.c
+ */
 #include <stdlib.h>
 #include <stdio.h>
 #include <termios.h>
 #include <unistd.h>
 #include <sys/select.h>
-#ifndef NRJBITS
-#define NRJBITS 16
-#endif
 #ifndef NRJWORD
 #define NRJWORD unsigned short
 #endif
-#define NRJSIZE (1 << NRJBITS)
+#define NRJWSIZE (sizeof(NRJWORD))
+#define NRJSIZE (1 << NRJWSIZE)
 #define MAXADDR ((NRJWORD) (NRJSIZE - 1))
-#define NRJWSIZE sizeof(NRJWORD)
 
 int kbhit() {
   struct timeval tv = { 0L, 0L };
@@ -22,26 +23,18 @@ int kbhit() {
   return select(1, &fds, NULL, NULL, &tv) > 0;
 }
 
-int getch() {
-  int r;
-  unsigned char c;
-  if((r = read(0, &c, 1)) < 0) return r;
-  else return c;
-}
-
 struct termios tty_opts_backup, tty_opts_raw;
 void restore_term() {
   tcsetattr(STDIN_FILENO, TCSANOW, &tty_opts_backup);
 }
 
 void nrj_in(NRJWORD *ctxid, NRJWORD *val) {
-  int x;
+  unsigned char c;
   if(*ctxid == (NRJWORD) 0) { /* for now, only emulate standard context id */
     *val = (NRJWORD) 0;
     if(kbhit()) {
-      x = getch();
-      if(x > -1)
-        *val = (NRJWORD) x;
+      if(read(0, &c, 1) > -1)
+        *val = (NRJWORD) c;
     }
   }
 }
@@ -51,26 +44,7 @@ void nrj_out(NRJWORD *ctxid, NRJWORD *val) {
     putchar((unsigned char) *val);
 }
 
-void nrj_load(NRJWORD* m, char *fname) {
-  FILE *prog = fopen(fname, "rb");
-  if(prog) {
-    fseek(prog, 0, SEEK_END);
-    int flen = ftell(prog);
-    fseek(prog, 0, SEEK_SET);
-    fread(m, NRJWSIZE, (flen/NRJWSIZE) & MAXADDR, prog);
-    fclose(prog);
-    cfmakeraw(&tty_opts_raw);
-    tcsetattr(STDIN_FILENO, TCSANOW, &tty_opts_raw);
-  }
-  else {
-    printf("NRJ16: could not open the input file %s\r\n", fname);
-    exit(1);
-  }
-}
-
-void nrj_run(char *program) {
-  NRJWORD mem[NRJSIZE], pc = (NRJWORD) 3; /* 0 - input, 1 -  output, 2 - I/O context, 3 - program start */
-  nrj_load(mem, program);
+void nrj_run(NRJWORD *mem, NRJWORD pc) { /* 0 - input, 1 -  output, 2 - I/O context, 3 - program start */
   while(pc != MAXADDR) {
     if(mem[0]) nrj_in(&mem[2], &mem[mem[0]]);
     mem[mem[pc]] = (~(mem[mem[pc]] | mem[mem[pc+1]])) & MAXADDR;
@@ -84,11 +58,29 @@ void nrj_run(char *program) {
 }
 
 int main(int argc, char* argv[]) {
+  if(argc > 1) {
+    NRJWORD mem[NRJSIZE];
+    FILE *prog = fopen(argv[1], "rb");
+    if(prog) {
+      /* load the program */
+      fseek(prog, 0, SEEK_END);
+      int flen = ftell(prog);
+      fseek(prog, 0, SEEK_SET);
+      fread(mem, NRJWSIZE, (flen/NRJWSIZE) & MAXADDR, prog);
+      fclose(prog);
+      /* prepare the terminal */
       tcgetattr(STDIN_FILENO, &tty_opts_backup);
       atexit(&restore_term);
-  if(argc > 1)
-    nrj_run(argv[1]);
+      cfmakeraw(&tty_opts_raw);
+      tcsetattr(STDIN_FILENO, TCSANOW, &tty_opts_raw);
+      /* start the engine */
+      nrj_run(mem, 3);
+    }
     else {
+      printf("NRJ16: could not open the input file %s\r\n", argv[1]);
+      return 1;
+    }
+  } else {
     puts("NRJ16: no binary specified\r");
     return 1;
   }