1 files changed, 66 insertions, 0 deletions
diff --git a/src/gas_assembly_generator.c b/src/gas_assembly_generator.c
new file mode 100644
index 0000000..d164b7d
--- /dev/null
+++ b/src/gas_assembly_generator.c
@@ -0,0 +1,66 @@
+/*
+* Copyright (C) 2023 Johnny Richard
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+#include "gas_assembly_generator.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static void gas_assembly_generator_visit_function(ast_visitor_t *visitor, ast_function_t *func);
+static void gas_assembly_generator_visit_return_stmt(ast_visitor_t *visitor, ast_return_stmt_t *return_stmt);
+
+void
+gas_assembly_generator_init(gas_assembly_generator_t *gen, FILE *out)
+{
+  assert(gen && out);
+  gen->super = (ast_visitor_t) {
+    .visit_function = &gas_assembly_generator_visit_function,
+    .visit_return_stmt = &gas_assembly_generator_visit_return_stmt
+  };
+  gen->out = out;
+}
+
+static void
+gas_assembly_generator_visit_function(ast_visitor_t *visitor, ast_function_t *func)
+{
+  assert(visitor && func);
+
+  if (!string_view_eq(func->name, string_view_from_str("main"))) {
+    fprintf(stderr, "[ERROR]: no main function has been defined!\n");
+    exit(EXIT_FAILURE);
+  }
+
+  gas_assembly_generator_t *gen = (gas_assembly_generator_t *) visitor;
+
+  fprintf(gen->out,".global _start\n");
+  fprintf(gen->out,".text\n");
+  fprintf(gen->out,"_start:\n");
+
+  ast_visitor_visit(visitor, &func->body);
+}
+
+static void
+gas_assembly_generator_visit_return_stmt(ast_visitor_t *visitor, ast_return_stmt_t *return_stmt)
+{
+  assert(visitor && return_stmt);
+  gas_assembly_generator_t *gen = (gas_assembly_generator_t *) visitor;
+
+  fprintf(gen->out, "  mov $1, %%al\n");
+  fprintf(gen->out, "  mov $%d, %%ebx\n", return_stmt->number);
+  fprintf(gen->out, "  int $0x80\n");
+}
+