nrj-oisc

commit 1022bb1cfb80b07890168f3100d8a5cdd65e943f
parent b7e539596dcbb82539906fa3fe974cf18cdffb5e
Author: Luxferre <lux@ferre>
Date:   Mon, 22 Aug 2022 19:55:24 +0300

even more optimizations

Diffstat:
M
nrj.c
 | 
42
+++++++++++++++++++++---------------------

1 file changed, 21 insertions(+), 21 deletions(-)
diff --git a/nrj.c b/nrj.c
@@ -1,6 +1,6 @@
 /*
- * NRJ (NOR and Reference Jump) OISC ANSI C emulator by Luxferre
- * Public domain
+ * NRJ (NOR and Reference Jump) OISC ANSI C emulator
+ * Created by Luxferre, 2022, public domain
  * Build with: cc -Os -o nrj nrj.c
  */
 #include <stdlib.h>
@@ -23,43 +23,43 @@ int kbhit() {
   return select(1, &fds, NULL, NULL, &tv) > 0;
 }
 
-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) {
+void nrj_in(NRJWORD *ctxid, NRJWORD *val) { /* context-dependent input handler */
   unsigned char c;
   if(*ctxid == (NRJWORD) 0) { /* for now, only emulate standard context id */
     *val = (NRJWORD) 0;
-    if(kbhit()) {
-      if(read(0, &c, 1) > -1)
-        *val = (NRJWORD) c;
-    }
+    if(kbhit() && read(0, &c, 1) > -1)
+      *val = (NRJWORD) c;
   }
 }
 
-void nrj_out(NRJWORD *ctxid, NRJWORD *val) {
+void nrj_out(NRJWORD *ctxid, NRJWORD *val) { /* context-dependent output handler */
   if(*ctxid == (NRJWORD) 0) /* for now, only emulate standard context id */
     putchar((unsigned char) *val);
 }
 
-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;
-    pc = mem[mem[pc+2]];
-    mem[0] = (NRJWORD) 0;
-    if(mem[1]) {
+void nrj_run(NRJWORD *mem, NRJWORD pc) { /* Main NRJ engine - just 12 lines of C within this function */
+  while(pc != MAXADDR) { /* halt if jumped to the last word */
+    if(mem[0]) { /* handle input if the first word is set, and clear it */
+      nrj_in(&mem[2], &mem[mem[0]]);
+      mem[0] = (NRJWORD) 0;
+    }
+    mem[mem[pc]] = (~(mem[mem[pc]] | mem[mem[pc+1]])) & MAXADDR; /* then perform the NOR operation */
+    pc = mem[mem[pc+2]]; /* then perform the reference jump operation */
+    if(mem[1]) { /* then handle output if the second word is set, and clear it */
       nrj_out(&mem[2], &mem[mem[1]]);
       mem[1] = (NRJWORD) 0;
     }
   }
 }
 
+struct termios tty_opts_backup, tty_opts_raw;
+void restore_term() {
+  tcsetattr(STDIN_FILENO, TCSANOW, &tty_opts_backup);
+}
+
 int main(int argc, char* argv[]) {
   if(argc > 1) {
-    NRJWORD mem[NRJSIZE];
+    NRJWORD mem[NRJSIZE]; /* NRJ memory: word 0 - input, 1 - output, 2 - I/O context, 3 - program start */
     FILE *prog = fopen(argv[1], "rb");
     if(prog) {
       /* load the program */