OBFI

Add optimisation comments

Diffstat

1 files changed, 12 insertions, 2 deletions

diff --git a/src/obfi.c b/src/obfi.c
index db7f355..7ed0754 100644
--- a/src/obfi.c
+++ b/src/obfi.c
@@ -76,31 +76,38 @@ int main(int ac, char *av[]) { A0 = av[0];
 
 	fread(fb, 1, fl, fi); fclose(fi);
 
+	// Remove comments from instruction buffer
 	char *p = fb, *q = fb;
 	for (; *p; ++p) if (strchr("><+-.,[]", *p)) { *q++ = *p; } *q = 0;
 
 	register size_t i, j;
 	for (i = 0; fb[i]; ++i) {
-	switch (fb[i]) {
+	switch (fb[i]) { // Generate initial operands
 	case '<': case '-': { fc[i] = -1; break; }
 	default:            { fc[i] =  1; break; }
 	}
-	switch (fb[i]) {
+	switch (fb[i]) { // Standardise instructions
 	case '>': case '<': { fb[i] = '>'; break; }
 	case '+': case '-': { fb[i] = '+'; break; }
 	}
 	}
 
+	// Compress movement and additive instructions
 	for (i = 0, j = 0; fb[i]; ++j) {
 		fb[j] = fb[i]; fc[j] = fc[i];
 		if (strchr(">+", fb[++i])) for (; fb[j] == fb[i]; fc[j] += fc[i++]);
 	} fb[j] = 0;
 
 	for (i = 0; fb[i]; ++i) {
+		// Optimise set to zero loops
 		if (cmp(fb + i, "[+]")) { fb[i] = 'Z'; fb[i + 1] = fb[i + 2] = ' '; }
+		
+		// Optimise move to zero loops
 		else if (cmp(fb + i, "[>]")) {
 			fb[i] = 'T'; fb[i + 1] = fb[i + 2] = ' '; fc[i] = fc[i + 1];
 		}
+		
+		// Optimise backward and forward move to loops
 		else if (cmp(fb + i, "[+>+>]") && fc[i + 1] == -1 && fc[i + 3] == 1 &&
 				fc[i + 2] == -fc[i + 4]) {
 			fb[i] = 'M';
@@ -115,10 +122,12 @@ int main(int ac, char *av[]) { A0 = av[0];
 		}
 	}
 
+	// Remove resultant spaces of loop optimisations
 	for (i = 0, j = 0; fb[i]; ++i) if (fb[i] != ' ') {
 		fb[j] = fb[i]; fc[j] = fc[i]; ++j;
 	} fb[j] = 0;
 
+	// Convert instructions to opcodes
 	for (i = 0; fb[i]; ++i) {
 		for (j = 0; fb[i] != ">+.,[]ZTM"[j]; ++j) {} fb[i] = j + 1;
 	}
@@ -126,6 +135,7 @@ int main(int ac, char *av[]) { A0 = av[0];
 	size_t l = 1024, t = 0, *S = malloc(l * sizeof (*S));
 	if (!S) { error(1, "%s", serr()); }
 
+	// Find and store bracket pairs
 	for (size_t i = 0; fb[i]; ++i) switch (fb[i]) {
 	case 5: { S[t++] = i; break; }
 	case 6: { --t; fc[S[t]] = i - S[t]; fc[i] = S[t] - i; break; }