From bdff7484617f2aae8b436d6e4d53eef5e58c89e2 Mon Sep 17 00:00:00 2001
From: sfja <sfja2004@gmail.com>
Date: Wed, 2 Apr 2025 16:32:51 +0200
Subject: [PATCH] don't use rsp in indirection

---
 asm/main.c    | 37 ++++++++++++++++++++++++++++++-------
 kern/main.asm | 12 +++---------
 2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/asm/main.c b/asm/main.c
index 0c305c8..04165aa 100644
--- a/asm/main.c
+++ b/asm/main.c
@@ -492,10 +492,32 @@ typedef enum {
     PStmtTy_Line,
     PStmtTy_Global,
     PStmtTy_Extern,
-    PStmtTy_Include,
     PStmtTy_Define,
 } PStmtTy;
 
+typedef struct {
+    PStmtTy ty;
+    union {
+        PLine* line;
+        char* ident;
+    };
+} PStmt;
+
+void pstmt_free(PStmt* stmt)
+{
+    switch (stmt->ty) {
+        case PStmtTy_Line:
+            pline_free(stmt->line);
+            break;
+        case PStmtTy_Global:
+        case PStmtTy_Extern:
+        case PStmtTy_Define:
+            free(stmt->ident);
+            break;
+    }
+    free(stmt);
+}
+
 typedef struct {
     Lexer lexer;
     Tok tok;
@@ -1063,7 +1085,7 @@ typedef struct {
 typedef struct {
     IdentResolver* re;
     Reporter* rep;
-    bool unresolve_is_error;
+    bool second_pass;
 } OperandEvaluator;
 
 static inline uint16_t eval_poperandty_unary(POperandTy ty, uint16_t operand)
@@ -1131,7 +1153,7 @@ EvaledOperand eval_operand_to_imm(
             const IdentResol* re
                 = ident_resolver_resolve(evaluator->re, operand->str);
             if (re == NULL) {
-                if (!evaluator->unresolve_is_error) {
+                if (!evaluator->second_pass) {
                     return (EvaledOperand) { .ty = EoTy_Imm, .imm = 0 };
                 }
                 REPORTF_ERROR("undefined identifier '%s'", operand->str);
@@ -2109,7 +2131,7 @@ int main(int argc, char** argv)
     OperandEvaluator evaluator = {
         .re = &resolver,
         .rep = &rep,
-        .unresolve_is_error = false,
+        .second_pass = false,
     };
 
     size_t chunk_capacity = 64;
@@ -2120,9 +2142,10 @@ int main(int argc, char** argv)
         int res = define_labels(&resolver, lines[i]->labels, ip, &rep);
         if (res != 0)
             errors_occured = true;
-        ip += pline_assemble(&evaluator, chunk, lines[i], &rep);
-        if (ip == 0)
+        uint16_t size = pline_assemble(&evaluator, chunk, lines[i], &rep);
+        if (size == 0)
             errors_occured = true;
+        ip += size;
     }
 
     if (errors_occured) {
@@ -2131,7 +2154,7 @@ int main(int argc, char** argv)
         goto leave_free_chunk;
     }
 
-    evaluator.unresolve_is_error = true;
+    evaluator.second_pass = true;
 
     FILE* output_fp = fopen(args.output_file, "wb");
     if (!output_fp) {
diff --git a/kern/main.asm b/kern/main.asm
index 311d4e9..21f1b1f 100644
--- a/kern/main.asm
+++ b/kern/main.asm
@@ -96,16 +96,10 @@ keyboard_interrupt:
     iret
 
 put_char:
-    ; push rbp
-    add rsp, rsp, 2
-    mov u16 [rsp], rbp
+    push rbp
     mov rbp, rsp
-    ; push r1
-    add rsp, rsp, 2
-    mov u16 [rsp], r1
-    ; push r2
-    add rsp, rsp, 2
-    mov u16 [rsp], r2
+    push r1
+    push r2
 
     mov r2, u16 [screen_y]
     mul r2, r2, 40 ; vcd_width_in_ch