add nasm backend

README.md

@@ -31,7 +31,7 @@ zig build cdb
 ## Feature wishlist
 
 * Update TinyCC backend, so host would not need to have it installed. Relies on host having include paths used by TinyCC.
-* Add more backends. Maybe LLVM, nasm or create my own
+* Add more backends. Maybe LLVM or create my own
 * Perform optimizations? Like removing not needed `[]` blocks which are known never to be ran? Idk, what could be optimized
 * Add WASM/Web build
 

build.zig

@@ -45,6 +45,11 @@ pub fn build(b: *Build) !void {
         }
     }
 
+    if (b.option(bool, "nasm", "Toggle 'nasm' compiler backend") orelse false) {
+        // TODO: Get nasm source code and embed it to executable.
+        exe.root_module.addCMacro("BF_BACKEND_NASM", "");
+    }
+
     zcc.createStep(b, "cdb", .{ .target = exe });
 
     b.installArtifact(exe);

examples/collatz.bf

@@ -0,0 +1,33 @@
+>,[
+    [
+        ----------[
+            >>>[>>>>]+[[-]+<[->>>>++>>>>+[>>>>]++[->+<<<<<]]<<<]
+            ++++++[>------<-]>--[>>[->>>>]+>+[<<<<]>-],<
+        ]>
+    ]>>>++>+>>[
+        <<[>>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<<]]<[>+<-]>]
+        >[>[>>>>]+[[-]<[+[->>>>]>+<]>[<+>[<<<<]]+<<<<]>>>[->>>>]+>+[<<<<]]
+        >[[>+>>[<<<<+>>>>-]>]<<<<[-]>[-<<<<]]>>>>>>>
+    ]>>+[[-]++++++>>>>]<<<<[[<++++++++>-]<.[-]<[-]<[-]<]<,
+]
+
+[The Collatz problem or 3n+1 problem is as follows. Take a natural number n.
+If it's even, halve it; if odd, triple it and add one. Repeat the process with
+the resulting number, and continue indefinitely. If n is 0, the resulting
+sequence is 0, 0, 0, 0... It is conjectured but not proven that for any
+positive integer n, the resulting sequence will end in 1, 4, 2, 1...
+See also http://www.research.att.com/projects/OEIS?Anum=A006577
+
+This program takes a series of decimal numbers, followed by linefeeds (10).
+The entire series is terminated by an EOF (0 or "no change"). For each number
+input, the program outputs, in decimal, the number of steps from that number
+to zero or one, when following the rule above. It's quite fast; on a Sun
+machine, it took three seconds for a random 640-digit number.
+
+One more note. This program was originally written for Tristan Parker's
+Brainfuck Texas Holdem contest, and won by default (it was the only entry);
+the version I submitted before the contest deadline is at
+http://www.hevanet.com/cristofd/brainfuck/oldcollatz.b
+
+Daniel B Cristofani (cristofdathevanetdotcom)
+http://www.hevanet.com/cristofd/brainfuck/]

examples/hello.bf

@@ -0,0 +1,3 @@
+>++++++++[<+++++++++>-]<.>++++[<+++++++>-]<+.+++++++..+++.>>++++++[<+++++++>-]<+
++.------------.>++++++[<+++++++++>-]<+.<.+++.------.--------.>>>++++[<++++++++>-
+]<+.

examples/sierpinski.bf

@@ -0,0 +1,12 @@
+[sierpinski.b -- display Sierpinski triangle
+(c) 2016 Daniel B. Cristofani
+http://brainfuck.org/]
+
+++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[
+    -<<<[
+        ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
+    ]>.>+[>>]>+
+]
+
+[Shows an ASCII representation of the Sierpinski triangle
+(iteration 5).]

include/bf_compiler.h

@@ -5,7 +5,8 @@
 #include <stdlib.h>
 
 enum bf_compiler_backend {
-	BF_COMPILER_TINYCC
+	BF_COMPILER_TINYCC,
+	BF_COMPILER_NASM,
 };
 
 struct bf_compiler {
@@ -14,7 +15,7 @@ struct bf_compiler {
 	uint32_t cell_size;
 };
 
-void bf_compiler_init(struct bf_compiler *compiler, uint32_t cell_size, uint32_t data_len);
+void bf_compiler_init(struct bf_compiler *compiler, enum bf_compiler_backend backend, uint32_t cell_size, uint32_t data_len);
 int bf_compiler_compile(struct bf_compiler *compiler, const char *output_filename, const char *program, size_t program_len);
 
 #endif //BF_COMPILER_H_

src/bf_compiler.c

@@ -7,11 +7,17 @@
 #include "bf_compiler_tinycc.c"
 #endif
 
-void bf_compiler_init(struct bf_compiler *compiler, uint32_t cell_size, uint32_t data_len)
+#ifdef BF_BACKEND_NASM
+#include "bf_compiler_nasm.c"
+#endif
+
+void bf_compiler_init(struct bf_compiler *compiler, enum bf_compiler_backend backend, uint32_t cell_size, uint32_t data_len)
 {
 	assert(cell_size == 8 || cell_size == 16 || cell_size == 32);
 	compiler->cell_size = cell_size;
 	compiler->data_len = data_len;
+
+	compiler->backend = backend;
 }
 
 int bf_compiler_compile(struct bf_compiler *compiler, const char *output_filename, const char *program, size_t program_len)
@@ -22,5 +28,11 @@ int bf_compiler_compile(struct bf_compiler *compiler, const char *output_filenam
 	}
 #endif
 
+#ifdef BF_BACKEND_NASM
+	if (compiler->backend == BF_COMPILER_NASM) {
+		return bf_compiler_compile_nasm(compiler, output_filename, program, program_len);
+	}
+#endif
+
 	return -1;
 }

src/bf_compiler_nasm.c

@@ -0,0 +1,129 @@
+#include "bf_compiler.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+static void fwrite_str(char *str, FILE *f)
+{
+	fwrite(str, strlen(str), 1, f);
+}
+
+static void fwrite_str_line(char *str, FILE *f)
+{
+	fwrite_str(str, f);
+	fwrite_str("\n", f);
+}
+
+static int bf_compiler_compile_nasm(struct bf_compiler *compiler, const char *output_filename, const char *program, size_t program_len)
+{
+	int rc = -1;
+	FILE *f = NULL;
+
+	if (compiler->cell_size != 8) {
+		return -1;
+	}
+
+	// TODO: Write to temp directory
+	f = fopen("tmp.asm", "w");
+	if (!f) {
+		goto err;
+	}
+
+	fwrite_str_line("section .bss", f);
+	char data_define[128] = { 0 };
+	snprintf(data_define, sizeof(data_define), "data resb %d", compiler->data_len);
+	fwrite_str_line(data_define, f);
+
+	fwrite_str_line("section .text", f);
+	fwrite_str_line("global _start", f);
+	fwrite_str_line("_start:", f);
+
+	fwrite_str_line("mov bl, 0", f);
+
+	uint32_t loop_stack[128] = { 0 };
+	uint32_t loop_stack_len = 0;
+
+	uint32_t last_loop_index = 0;
+	for (int i = 0; i < program_len; i++) {
+		char inst = program[i];
+
+		if (inst == '>') {
+			fwrite_str_line("; >", f);
+			fwrite_str_line("inc bl", f);
+		} else if (inst == '<') {
+			fwrite_str_line("; <", f);
+			fwrite_str_line("dec bl", f);
+		} else if (inst == '+') {
+			fwrite_str_line("; +", f);
+			fwrite_str_line("inc byte [data + rbx]", f);
+		} else if (inst == '-') {
+			fwrite_str_line("; -", f);
+			fwrite_str_line("dec byte [data + rbx]", f);
+		} else if (inst == '.') {
+			fwrite_str_line("; .", f);
+			// sys_write
+			fwrite_str_line("mov rax, 1", f); // Syscall id
+			fwrite_str_line("mov rdi, 1", f); // fd
+			fwrite_str_line("lea rsi, byte [data + rbx]", f); // buff
+			fwrite_str_line("mov rdx, 1", f); // count
+			fwrite_str_line("syscall", f);
+		} else if (inst == ',') {
+			fwrite_str_line("; ,", f);
+			// sys_read
+			fwrite_str_line("mov rax, 0", f); // Syscall id
+			fwrite_str_line("mov rdi, 0", f); // fd
+			fwrite_str_line("lea rsi, byte [data + rbx]", f); // buff
+			fwrite_str_line("mov rdx, 1", f); // count
+			fwrite_str_line("syscall", f);
+		} else if (inst == '[') {
+			fwrite_str_line("; [", f);
+
+			uint32_t loop_index = last_loop_index;
+			last_loop_index++;
+
+			loop_stack[loop_stack_len++] = loop_index;
+
+			char start_label[128] = { 0 };
+			snprintf(start_label, sizeof(start_label), "S%d_start:", loop_index);
+			fwrite_str_line(start_label, f);
+
+			fwrite_str_line("cmp byte [data + rbx], 0", f);
+
+			char jump_inst[128] = { 0 };
+			snprintf(jump_inst, sizeof(jump_inst), "jz S%d_end", loop_index);
+			fwrite_str_line(jump_inst, f);
+		} else if (inst == ']') {
+			fwrite_str_line("; ]", f);
+			uint32_t loop_index = loop_stack[--loop_stack_len];
+
+			char jump_to_start[128] = { 0 };
+			snprintf(jump_to_start, sizeof(jump_to_start), "jmp S%d_start", loop_index);
+			fwrite_str_line(jump_to_start, f);
+
+			char end_label[128] = { 0 };
+			snprintf(end_label, sizeof(end_label), "S%d_end:", loop_index);
+			fwrite_str_line(end_label, f);
+		}
+	}
+
+	fwrite_str_line("; exit(0)", f);
+	fwrite_str_line("mov rax, 60", f);
+	fwrite_str_line("mov rdi, 0", f);
+	fwrite_str_line("syscall", f);
+
+	fclose(f);
+	f = NULL;
+
+	// TODO: Use exec instead of system
+	// TODO: Don't hardcode the platform
+	system("nasm -felf64 tmp.asm -o tmp.o");
+
+	char ld_command[256] = { 0 };
+	snprintf(ld_command, sizeof(ld_command), "ld tmp.o -o %s", output_filename);
+	system(ld_command);
+	rc = 0;
+err:
+	if (f) fclose(f);
+	return rc;
+}

src/main.c

@@ -50,6 +50,11 @@ err:
 	return result;
 }
 
+void show_usage() {
+	printf("Usage: brainfuck run <filename>\n");
+	printf("       brainfuck compile [--nasm] [--tinycc] <input-file> <output-file>\n");
+}
+
 int run_command(int argc, const char **argv) {
 	const char *filename = argv[0];
 
@@ -71,15 +76,41 @@ int run_command(int argc, const char **argv) {
 }
 
 int compile_command(int argc, const char **argv) {
-	const char *input_filename = argv[0];
-	const char *output_filename = argv[1];
+	enum bf_compiler_backend backend = BF_COMPILER_TINYCC;
+	uint32_t cell_size = 8; // TODO: Make this configurable using CLI
+	uint32_t data_len = 256; // TODO: Make this configurable using CLI
+
+	int last_arg = 0;
+	for (int i = 0; i < argc; i++) {
+		last_arg = i;
+		if (strncmp(argv[i], "--", sizeof("--")-1)) {
+			break;
+		}
+
+		if (!strncmp(argv[i], "--nasm", sizeof("--nasm"))) {
+			backend = BF_COMPILER_NASM;
+		} else if (!strncmp(argv[i], "--tinycc", sizeof("--tinycc"))) {
+			backend = BF_COMPILER_TINYCC;
+		} else {
+			printf("Invalid argument: \"%s\"", argv[i]);
+			return -1;
+		}
+	}
+
+	if (last_arg+2 != argc) {
+		show_usage();
+		return -1;
+	}
+
+	const char *input_filename = argv[last_arg];
+	const char *output_filename = argv[last_arg+1];
 
 	size_t program_len = 0;
 	char *program = read_file(input_filename, &program_len);
 	assert(program != NULL);
 
 	struct bf_compiler compiler = { 0 };
-	bf_compiler_init(&compiler, 16, 4096);
+	bf_compiler_init(&compiler, backend, cell_size, data_len);
 
 	if (bf_compiler_compile(&compiler, output_filename, program, program_len)) {
 		printf("ERROR: Failed to compile program\n");
@@ -89,11 +120,6 @@ int compile_command(int argc, const char **argv) {
 	return 0;
 }
 
-void show_usage() {
-	printf("Usage: brainfuck run <filename>\n");
-	printf("       brainfuck compile <input-file> <output-file>\n");
-}
-
 int main(int argc, const char **argv) {
 	if (argc >= 3 && !strncmp(argv[1], "run", sizeof("run"))) {
 		return run_command(argc - 2, argv + 2);