From e5d311f91ecda870c8e50d3f9c860b99e244a908 Mon Sep 17 00:00:00 2001
From: Nic Gaffney <gaffney_nic@protonmail.com>
Date: Sun, 28 Jul 2024 01:33:19 -0500
Subject: Added const, var, and assigning variables.

---
 src/codegen.zig | 103 +++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 87 insertions(+), 16 deletions(-)

(limited to 'src/codegen.zig')

diff --git a/src/codegen.zig b/src/codegen.zig
index a200e23..98501c2 100644
--- a/src/codegen.zig
+++ b/src/codegen.zig
@@ -18,35 +18,106 @@ pub const Generator = struct {
         self.code.deinit();
     }
 
-    fn genExit(self: *Generator, expr: parse.NodeExpr) ![]const u8 {
-        return try std.fmt.allocPrint(self.allocator,
-            \\  mov rax, 60
-            \\  mov rdi, {d}
-            \\  syscall
+    fn genExit(self: *Generator, expr: parse.NodeExpr) !void {
+        const newCode =
+            switch (expr) {
+            .intLit => try std.fmt.allocPrint(self.allocator,
+                \\  mov rax, 60
+                \\  mov rdi, {d}
+                \\  syscall
+                \\
+            , .{
+                expr.intLit.intlit.intLit,
+            }),
+            .ident => try std.fmt.allocPrint(self.allocator,
+                \\  mov rax, 60
+                \\  mov rdi, [{s}]
+                \\  syscall
+                \\
+            , .{
+                expr.ident.ident.ident,
+            }),
+        };
+        try self.code.appendSlice(newCode);
+        self.allocator.free(newCode);
+    }
+
+    fn genValue(self: *Generator, value: parse.NodeValue) !void {
+        const str = try std.fmt.allocPrint(self.allocator,
+            \\section .data
+            \\  {s}: dw {d}
             \\
-        , .{switch (expr) {
-            .intLit => expr.intLit.intlit.intLit,
+        , .{ value.ident.ident, switch (value.value) {
+            .intLit => value.value.intLit.intlit.intLit,
             else => return error.NotImplemented,
-        }});
+        } });
+        defer self.allocator.free(str);
+        try self.code.insertSlice(0, str);
     }
 
-    fn genValue(self: *Generator) ![]const u8 {
-        _ = self;
-        return error.NotImplemented;
+    fn genAssign(self: *Generator, assign: parse.NodeAssign) !void {
+        const newCode =
+            switch (assign.value) {
+            .intLit => try std.fmt.allocPrint(self.allocator,
+                \\  mov rax, {d}
+                \\  mov [{s}], rax
+                \\
+            , .{
+                assign.value.intLit.intlit.intLit,
+                assign.ident.ident,
+            }),
+            .ident => try std.fmt.allocPrint(self.allocator,
+                \\  mov rax, [{s}]
+                \\  mov [{s}], rax
+                \\
+            , .{
+                assign.value.ident.ident.ident,
+                assign.ident.ident,
+            }),
+        };
+        try self.code.appendSlice(newCode);
+        self.allocator.free(newCode);
     }
 
     pub fn generate(self: *Generator) ![]const u8 {
         try self.code.appendSlice(
-            \\global _start:
+            \\section .text
+            \\  global _start
+            \\_start:
             \\
         );
         for (self.root) |stmt| {
-            const code = switch (stmt) {
+            switch (stmt) {
                 .exit => try self.genExit(stmt.exit.expr),
-                .value => try self.genValue(),
-            };
-            try self.code.appendSlice(code);
+                .value => try self.genValue(stmt.value),
+                .assign => try self.genAssign(stmt.assign),
+            }
         }
         return self.code.items;
     }
 };
+
+test "Codegen exit" {
+    const tok = @import("tokenize.zig");
+    const expect = std.testing.expect;
+    const src = "exit 120;";
+    var tokenizer = tok.Tokenizer.init(std.testing.allocator, src);
+    defer tokenizer.deinit();
+    const toks = try tokenizer.tokenize();
+    var parser = parse.Parser.init(std.testing.allocator, toks);
+    defer parser.deinit();
+    const parseTree = try parser.parse();
+    var gen = Generator.init(std.testing.allocator, parseTree);
+    defer gen.deinit();
+    const actual = try gen.generate();
+    const expected =
+        \\section .text
+        \\  global _start
+        \\_start:
+        \\  mov rax, 60
+        \\  mov rdi, 120
+        \\  syscall
+        \\
+    ;
+    try expect(std.mem.eql(u8, actual, expected));
+}
-- 
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