Remove `putc` intrinsic and replace with `write(fd, buf, size)`

`putc`, `puts`, and `putnum` in `std/common.cup` are now implemented
in terms of the `write()` syscall.

4 files changed, 30 insertions, 10 deletions

diff --git a/src/builtins.c b/src/builtins.c
index 591caeb..3922d54 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -29,11 +29,13 @@ void initialize_builtins()
     push_builtin(node);
 
     node = Node_new(AST_BUILTIN);
-    node->func.name = "putc";
+    node->func.name = "write";
     node->func.return_type = type_new(TYPE_INT);
-    node->func.num_args = 1;
-    node->func.args = (Variable *)calloc(sizeof(Variable), 2);
-    node->func.args[0] = (Variable){"arg", type_new(TYPE_INT), 0};
+    node->func.num_args = 3;
+    node->func.args = (Variable *)calloc(sizeof(Variable), 3);
+    node->func.args[0] = (Variable){"fd", type_new(TYPE_INT), 0};
+    node->func.args[1] = (Variable){"buf", type_new_ptr(TYPE_CHAR), 0}; 
+    node->func.args[2] = (Variable){"size", type_new(TYPE_INT), 0};
     push_builtin(node);
 }
 
diff --git a/src/generator.c b/src/generator.c
index f422657..aace3bc 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -170,6 +170,15 @@ void generate_expr_into_rax(Node *expr, FILE *out)
         fprintf(out, "    cqo\n");
         fprintf(out, "    idiv rbx\n");
 
+    } else if (expr->type == OP_MOD) {
+        generate_expr_into_rax(expr->binary.right, out);
+        fprintf(out, "    push rax\n");
+        generate_expr_into_rax(expr->binary.left, out);
+        fprintf(out, "    pop rbx\n");
+        fprintf(out, "    cqo\n");
+        fprintf(out, "    idiv rbx\n");
+        fprintf(out, "    mov rax, rdx\n");
+
     } else if (expr->type == OP_MUL) {
         generate_expr_into_rax(expr->binary.right, out);
         fprintf(out, "    push rax\n");
@@ -507,13 +516,12 @@ void generate_builtins(FILE *out)
 
     /////////////////////////////////////////////////////////////////
 
-    // Print out a single character
+    // Write syscall
     fprintf(out,
-        "func_putc:\n"
-        "    mov rdi, 1\n"   // stdout
-        "    mov rsi, rsp\n"
-        "    add rsi, 8\n"
-        "    mov rdx, 1\n" // 1 byte
+        "func_write:\n"
+        "    mov rdi, [rsp+8]\n"   // stdout
+        "    mov rsi, [rsp+16]\n"
+        "    mov rdx, [rsp+24]\n" // 1 byte
     );
     make_syscall(SYS_write, out);
     fprintf(out, "    ret\n");
diff --git a/src/types.c b/src/types.c
index 31edc4b..b2709f8 100644
--- a/src/types.c
+++ b/src/types.c
@@ -59,6 +59,14 @@ Type *type_new(DataType type)
     return self;
 }
 
+Type *type_new_ptr(DataType type)
+{
+    Type *self = type_new(TYPE_PTR);
+    self->ptr = type_new(type);
+    return self;
+}
+
+
 bool is_string_type(Type *type)
 {
     return type 
diff --git a/src/types.h b/src/types.h
index a1f6923..73b5b63 100644
--- a/src/types.h
+++ b/src/types.h
@@ -19,6 +19,8 @@ typedef struct data_type_node {
 } Type;
 
 Type *type_new(DataType type);
+Type *type_new_ptr(DataType type);
+
 i64 size_for_type(Type *type);
 char *type_to_str(Type *type);