From f8ff357045c7126521f7ec8f8f03ac886634eb80 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Fri, 13 Mar 2026 10:15:07 +0100
Subject: [PATCH] Align the stack upon function entry

---
 boot/stage19/cl.elna |  2 ++
 boot/stage20/cl.elna | 45 ++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/boot/stage19/cl.elna b/boot/stage19/cl.elna
index ed2937d..5a3916e 100644
--- a/boot/stage19/cl.elna
+++ b/boot/stage19/cl.elna
@@ -1516,6 +1516,8 @@ begin
 		elna_alloc_operation_target(instruction, variable_map)
 	elsif instruction^.operator = ElnaRtlOperator._xor then
 		elna_alloc_operation_target(instruction, variable_map)
+	elsif instruction^.operator = ElnaRtlOperator.div then
+		elna_alloc_operation_target(instruction, variable_map)
 	elsif instruction^.operator = ElnaRtlOperator.rem then
 		elna_alloc_operation_target(instruction, variable_map)
 	elsif instruction^.operator = ElnaRtlOperator.slt then
diff --git a/boot/stage20/cl.elna b/boot/stage20/cl.elna
index a4adfc5..267da48 100644
--- a/boot/stage20/cl.elna
+++ b/boot/stage20/cl.elna
@@ -1565,6 +1565,8 @@ begin
 		instruction := elna_alloc_binary(instructions, instruction, variable_map)
 	elsif instruction^.operator = ElnaRtlOperator._xor then
 		instruction := elna_alloc_binary(instructions, instruction, variable_map)
+	elsif instruction^.operator = ElnaRtlOperator.div then
+		instruction := elna_alloc_binary(instructions, instruction, variable_map)
 	elsif instruction^.operator = ElnaRtlOperator.rem then
 		instruction := elna_alloc_binary(instructions, instruction, variable_map)
 	elsif instruction^.operator = ElnaRtlOperator.slt then
@@ -1615,13 +1617,13 @@ begin
 
 		(* Write the prologue. *)
 		printf("\taddi sp, sp, -%i\n\tsw ra, %i(sp)\n\tsw s0, %i(sp)\n\taddi s0, sp, %i\n\0",
-				operand_value + 8, operand_value + 4, operand_value, operand_value + 8);
+				operand_value, operand_value - 4, operand_value - 8, operand_value);
 		fflush(nil)
 	elsif instruction^.operator = ElnaRtlOperator.ret then
 		operand_value := instruction^.operands[1].value;
 
 		(* Write the epilogue. *)
-		printf("\tlw ra, %i(sp)\n\tlw s0, %i(sp)\n\taddi sp, sp, %i\n\0", operand_value + 4, operand_value, operand_value + 8);
+		printf("\tlw ra, %i(sp)\n\tlw s0, %i(sp)\n\taddi sp, sp, %i\n\0", operand_value - 4, operand_value - 8, operand_value);
 		fflush(nil)
 	elsif instruction^.operator = ElnaRtlOperator.nop then
 	else
@@ -1750,6 +1752,44 @@ begin
 	elna_alloc_procedure(pair^.code)
 end;
 
+proc elna_fixup_instructions(instructions: ^ElnaList);
+var
+	instruction: ^ElnaRtlInstruction;
+	stack_size: Word;
+begin
+	instruction := instructions^.first;
+	stack_size := instruction^.operands[1].value;
+
+	(* Align the stack. *)
+	stack_size := stack_size + 8;
+	if stack_size % 16 then
+		stack_size := stack_size + 16
+	end;
+	stack_size := stack_size / 16;
+	stack_size := stack_size * 16;
+
+	instruction^.operands[1].value := stack_size;
+	instruction := instructions^.last;
+	instruction^.operands[1].value := stack_size
+end;
+
+proc elna_fixup_procedure(rtl_declaration: ^ElnaRtlProcedure);
+begin
+	.elna_fixup_procedure_loop;
+
+	elna_fixup_instructions(@rtl_declaration^.body);
+
+	rtl_declaration := rtl_declaration^.next;
+	if rtl_declaration <> nil then
+		goto elna_fixup_procedure_loop
+	end
+end;
+
+proc elna_fixup_module(pair: ^ElnaInstructionModule);
+begin
+	elna_fixup_procedure(pair^.code)
+end;
+
 proc elna_riscv_module(pair: ^ElnaInstructionModule);
 var
 	compiler_strings_copy: Word;
@@ -4378,6 +4418,7 @@ begin
 		tac := elna_tac_module_declaration(parser_node);
 		rtl := elna_rtl_module_declaration(tac);
 		elna_alloc_module(rtl);
+		elna_fixup_module(rtl);
 		elna_riscv_module(rtl);
 	end;