The compilation process now includes *very* minimal code optimization.

7 files changed, 51 insertions, 13 deletions

diff --git a/.gitignore b/.gitignore
index 92436a3..ffee194 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 skullfuck
-test
-test.c
+run_tests
+run_tests.c
diff --git a/README.md b/README.md
index 0f8dc25..ad30ca6 100644
--- a/README.md
+++ b/README.md
@@ -1,17 +1,12 @@
 Skullfuck
 =========
-Skullfuck is a dead simple, non-optimizing compiler for Brainfuck, contained in a single C source file. It outputs binaries targeting amd64 Linux.
+Skullfuck is a dead simple, non-optimizing compiler for Brainfuck, contained in a single C source file. It outputs binaries targeting x86_64 and i686 Linux.
 
 It depends on GNU Binutils, or any compatible implementation of `as` and `ld`.
 
 A good explanation of the history and design behind the language can be found in [the Wikipedia article.](https://en.wikipedia.org/wiki/Brainfuck)
 
 
-Undefined Behavior
-------------------
-The Brainfuck programming language is extremely limited in its specification, and some operations don't have a defined behavior - specifically, operations on an out-of-bounds data pointer are undefined. UB is allowed, but do not expect it to work equally on all platforms.
-
-
 TODO
 ----
 * *BSD targeted binaries.
diff --git a/skullfuck.c b/skullfuck.c
index 7d9e0a8..b40e903 100644
--- a/skullfuck.c
+++ b/skullfuck.c
@@ -29,9 +29,13 @@
 #define ARCH         "x86_64"
 #define OS           "Linux"
 #define INC_DATA_PTR "\tincq %rsi\n"
+#define ADD_DATA_PTR "\taddq $0x%x, %%rsi\n"
 #define DEC_DATA_PTR "\tdecq %rsi\n"
+#define SUB_DATA_PTR "\tsubq $0x%x, %%rsi\n"
 #define INC_DATA     "\tincb (%rsi)\n"
+#define ADD_DATA     "\taddb $0x%x, (%%rsi)\n"
 #define DEC_DATA     "\tdecb (%rsi)\n"
+#define SUB_DATA     "\tsubb $0x%x, (%%rsi)\n"
 #define PRINT_DATA   "\tmovq $0x01, %rax\n" \
                      "\tmovq $0x01, %rdi\n" \
                      "\tsyscall\n"
@@ -58,9 +62,13 @@
 #define ARCH         "i686"
 #define OS           "Linux"
 #define INC_DATA_PTR "\tincl %ecx\n"
+#define ADD_DATA_PTR "\taddl $0x%x, %%ecx\n"
 #define DEC_DATA_PTR "\tdecl %ecx\n"
+#define SUB_DATA_PTR "\tsubl $0x%x, %%ecx\n"
 #define INC_DATA     "\tincb (%ecx)\n"
+#define ADD_DATA     "\taddb $0x%x, (%%ecx)\n"
 #define DEC_DATA     "\tdecb (%ecx)\n"
+#define SUB_DATA     "\tsubb $0x%x, (%%ecx)\n"
 #define PRINT_DATA   "\tmovl $0x04, %eax\n" \
                      "\tmovl $0x01, %ebx\n" \
                      "\tint $0x80\n"
@@ -121,26 +129,57 @@ static int pop_loop_index(struct loop_stack *s) {
 }
 
 
+/* Minor optimization subroutine. Increments the `in` pointer to beyond
+   the collection of adjacent `op` characters, and returns the number
+   of operations counted. */
+static int reduce(char **in, char op) {
+    int  i;
+    for (i = 0; (*in)[i] == op; i++);
+    *in += i - 1;
+    return i;
+}
+
+
 /* Converts the brainfuck instructions read from `in` to assembly
    instructions and writes them to `out`. `in` is expected to be
    null-terminated. */
 static void write_instructions(FILE *out, char *in) {
-    int               next_loop = 0, cur_loop = 0;
+    int               next_loop = 0, cur_loop = 0, op_count;
     struct loop_stack *loops = calloc(sizeof(struct loop_stack), 1);
 
     for (char *cur = in; *cur != '\0'; cur++) {
         switch(*cur) {
             case '>':
-                fputs(INC_DATA_PTR, out);
+                op_count = reduce(&cur, '>');
+                if (op_count > 1) {
+                    fprintf(out, ADD_DATA_PTR, op_count);
+                } else {
+                    fputs(INC_DATA_PTR, out);
+                }
                 break;
             case '<':
-                fputs(DEC_DATA_PTR, out);
+                op_count = reduce(&cur, '<');
+                if (op_count > 1) {
+                    fprintf(out, SUB_DATA_PTR, op_count);
+                } else {
+                    fputs(DEC_DATA_PTR, out);
+                }
                 break;
             case '+':
-                fputs(INC_DATA, out);
+                op_count = reduce(&cur, '+');
+                if (op_count > 1) {
+                    fprintf(out, ADD_DATA, op_count);
+                } else {
+                    fputs(INC_DATA, out);
+                }
                 break;
             case '-':
-                fputs(DEC_DATA, out);
+                op_count = reduce(&cur, '-');
+                if (op_count > 1) {
+                    fprintf(out, SUB_DATA, op_count);
+                } else {
+                    fputs(DEC_DATA, out);
+                }
                 break;
             case '.':
                 fputs(PRINT_DATA, out);
@@ -223,6 +262,10 @@ static void create_binary(struct params p) {
             wait(NULL);
         }
     }
+
+    if (!p.compile_only)
+        remove("/tmp/skullfuck_tmp.s");
+    remove("/tmp/skullfuck_tmp.o");
 }
 
 
diff --git a/examples/hello_world.bf b/test/hello_world.bf
index ea2b641..ea2b641 100644
--- a/examples/hello_world.bf
+++ b/test/hello_world.bf
diff --git a/examples/hello_world_commented.bf b/test/hello_world_commented.bf
index fff532c..fff532c 100644
--- a/examples/hello_world_commented.bf
+++ b/test/hello_world_commented.bf
diff --git a/examples/rot13.bf b/test/rot13.bf
index e9e82be..e9e82be 100644
--- a/examples/rot13.bf
+++ b/test/rot13.bf
diff --git a/examples/rot13_commented.bf b/test/rot13_commented.bf
index 85a97fa..85a97fa 100644
--- a/examples/rot13_commented.bf
+++ b/test/rot13_commented.bf