1 files changed, 47 insertions, 11 deletions

diff --git a/codegen.c b/codegen.c
index 9d7f183..4e9f63a 100644
--- a/codegen.c
+++ b/codegen.c
@@ -1,6 +1,7 @@
 #include "ccc.h"
 #include "codegen.h"
 #include "scope.h"
+#include "register.h"
 #include <stdlib.h>
 #include <stdio.h>
 
@@ -14,17 +15,25 @@
 
 static const struct storage_location RV_LOC = {
     .type = REGISTER,
-    .label = "rax",
+    .reg = &RAX,
 };
+#define FULL_REG_SZ 8
 
 static struct scope* scope;
 
 static void emit_storage_loc(
     FILE* outfile,
-    const struct storage_location* loc
+    const struct storage_location* loc,
+    unsigned long long sz
 ) {
     switch (loc->type) {
         case REGISTER:
+            if (sz > 4) fprintf(outfile, "%s", loc->reg->qword);
+            else if (sz > 2) fprintf(outfile, "%s", loc->reg->dword);
+            // TODO: for word and byte make sure moving into these zeroes the high register
+            else if (sz > 1) fprintf(outfile, "%s", loc->reg->word);
+            else fprintf(outfile, "%s", loc->reg->byte);
+            break;
         case JMP_LABEL:
             fprintf(outfile, "%s", loc->label);
             break;
@@ -45,7 +54,7 @@ static void emit_int_lit(
 ) {
     if (storage != NULL) {
         fprintf(outfile, "\tmov ");
-        emit_storage_loc(outfile, storage);
+        emit_storage_loc(outfile, storage, FULL_REG_SZ);
         fprintf(outfile, ", %lld\n", node->val);
     }
 }
@@ -61,9 +70,9 @@ static void emit_var_ref(
             CGEN_PANIC("reference to undefined variable %s", node->ident);
 
         fprintf(outfile, "\tmov ");
-        emit_storage_loc(outfile, storage);
+        emit_storage_loc(outfile, storage, var_def.sz);
         fprintf(outfile, ", ");
-        emit_storage_loc(outfile, &var_def.loc);
+        emit_storage_loc(outfile, &var_def.loc, var_def.sz);
         fprintf(outfile, "\n");
     }
 }
@@ -108,6 +117,7 @@ static void emit_var_decl(FILE* outfile, const struct var_decl_node* node) {
             .type = BP_OFFSET,
             .offset = scope->bp_offset,
         },
+        .sz = type_sz,
     });
 }
 
@@ -137,10 +147,13 @@ static void emit_stmt_group(FILE* outfile, const struct group_node* node) {
         fprintf(outfile, "\tmov rsp, rbp\n");
     else {
         fprintf(outfile, "\tlea rsp, ");
-        emit_storage_loc(outfile, &(struct storage_location) {
-            .type = BP_OFFSET,
-            .offset = scope->bp_offset,
-        });
+        emit_storage_loc(
+            outfile,
+            &(struct storage_location) {
+                .type = BP_OFFSET,
+                .offset = scope->bp_offset,
+            },
+            FULL_REG_SZ);
         fprintf(outfile, "\n");
     }
 }
@@ -170,18 +183,41 @@ static void emit_fn_decl(FILE* outfile, const struct fn_decl_node* node) {
     scope_push(&scope);
     scope->bp_offset = 0;
 
+    long long spilled_bp_ofs = -16; // return address + old bp
+    unsigned long long arg_regnum = 0;
     struct var_decl_node* args_node = node->args_head;
     while (args_node != NULL) {
         unsigned long long type_sz = get_type_size(&args_node->type);
 
         scope->bp_offset += type_sz;
-        scope_define_var(scope, (struct var_def) {
+        struct var_def var_def = {
             .name = args_node->ident,
             .loc = {
                 .type = BP_OFFSET,
                 .offset = scope->bp_offset,
             },
-        });
+            .sz = type_sz,
+        };
+        scope_define_var(scope, var_def);
+
+        struct storage_location arg_src;
+        if (arg_regnum < CC_N_REGS) {
+            arg_src = (struct storage_location) {
+                .type = REGISTER,
+                .reg = CALLING_CONV[arg_regnum++]
+            };
+        } else {
+            arg_src = (struct storage_location) {
+                .type = BP_OFFSET,
+                .offset = spilled_bp_ofs,
+            };
+            spilled_bp_ofs -= type_sz;
+        }
+        fprintf(outfile, "\tmov ");
+        emit_storage_loc(outfile, &var_def.loc, type_sz);
+        fprintf(outfile, ", ");
+        emit_storage_loc(outfile, &arg_src,type_sz);
+        fprintf(outfile, "\n");
 
         args_node = args_node->next;
     }