1 files changed, 49 insertions, 1 deletions

diff --git a/src/gas_assembly_generator.c b/src/gas_assembly_generator.c
index 2d6b993..26bf3f9 100644
--- a/src/gas_assembly_generator.c
+++ b/src/gas_assembly_generator.c
@@ -22,6 +22,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+size_t available_calling_registers = 6;
+char *calling_registers[] = { "rdi", "rsi", "rdx", "rcx", "r8", "r9" };
+
 static void
 gas_assembly_generator_binary_operation(gas_assembly_generator_t *gen, ast_binary_operation_t *binary_operation);
 
@@ -183,6 +186,7 @@ gas_assembly_generator_compile(gas_assembly_generator_t *gen, ast_node_t *ast)
     case AST_IF_STMT:
       gas_assembly_generator_compile_if_stmt(gen, &ast->data.if_stmt);
       break;
+    case AST_FUNCTION_PARAMETER:
     case AST_UNKOWN_NODE:
       assert(false && "unreachable");
   }
@@ -204,10 +208,27 @@ gas_assembly_generator_compile_function(gas_assembly_generator_t *gen, ast_funct
   uint64_t previous_index = gen->return_label_index;
   uint64_t return_label_index = gen->return_label_index = gen->counter_label_index++;
 
-  fprintf(gen->stream, SVFMT ":\n", SVARG(&func->identifier.name));
+  assert((func->prototype.parameters->size <= available_calling_registers) &&
+         "Not enough registers to process this function. Stack parameters will come soon.");
+
+  fprintf(gen->stream, SVFMT ":\n", SVARG(&func->prototype.identifier.name));
   fprintf(gen->stream, "  push %%rbp\n");
   fprintf(gen->stream, "  mov %%rsp, %%rbp\n");
 
+  for (size_t i = 0; i < func->prototype.parameters->size; i++) {
+    char *reg = calling_registers[i];
+    ast_node_t *parameter = vector_at(func->prototype.parameters, i);
+
+    assert(parameter->kind == AST_FUNCTION_PARAMETER);
+
+    gen->stack_offset -= 8;
+
+    fprintf(gen->stream, "  mov %%%s, %d(%%rbp)\n", reg, gen->stack_offset);
+
+    ref_set_variable_reference_stack_offset(
+      gen->refs, &parameter->data.function_parameter.identifier, gen->stack_offset);
+  }
+
   gas_assembly_generator_compile(gen, func->body);
 
   fprintf(gen->stream, ".L%ld:\n", return_label_index);
@@ -215,11 +236,38 @@ gas_assembly_generator_compile_function(gas_assembly_generator_t *gen, ast_funct
   fprintf(gen->stream, "  ret\n");
 
   gen->return_label_index = previous_index;
+  gen->stack_offset = 0;
 }
 
 static void
 gas_assembly_generator_compile_function_call(gas_assembly_generator_t *gen, ast_function_call_t *func_call)
 {
+  assert((func_call->arguments->size <= available_calling_registers) &&
+         "Not enough registers to process this function. Stack parameters will come soon.");
+
+  for (size_t i = 0; i < func_call->arguments->size; i++) {
+    char *reg = calling_registers[i];
+    ast_node_t *argument = vector_at(func_call->arguments, i);
+
+    gas_assembly_generator_compile(gen, argument);
+
+    switch (gen->latest_evaluation.kind) {
+      case EVALUATION_RESULT_AS_LITERAL_INTEGER:
+        fprintf(gen->stream, "  mov $%ld, %%%s\n", gen->latest_evaluation.data.literal_int, reg);
+        break;
+      case EVALUATION_RESULT_ON_RAX:
+        fprintf(gen->stream, "  mov %%rax, %%%s\n", reg);
+        break;
+      case EVALUATION_RESULT_ON_STACK:
+        fprintf(gen->stream, "  mov %d(%%rbp), %%%s\n", gen->latest_evaluation.data.stack_offset, reg);
+        break;
+      case EVALUATION_RESULT_AS_LITERAL_BOOL:
+        fprintf(gen->stream, "  mov %d(%%rbp), %%%s\n", gen->latest_evaluation.data.literal_bool, reg);
+        break;
+      case EVALUATION_RESULT_VOID:
+        assert(false && "Unexpected");
+    }
+  }
   fprintf(gen->stream, "  call " SVFMT "\n", SVARG(&func_call->identifier->name));
   gas_assembly_generator_set_latest_evaluation_to_rax(gen);
 }