From 8a7f8bc09c88e9446d475127a82df23a1dcb0c75 Mon Sep 17 00:00:00 2001
From: Mike Pavone <pavone@retrodev.com>
Date: Mon, 23 Jun 2014 13:12:04 -0400
Subject: Ensure proper stack alignment when the Z80 calls into C code. This
 fixes a crash in optimized builds on OSX

---
 zruntime.S | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'zruntime.S')

diff --git a/zruntime.S b/zruntime.S
index 1883239..a7bac3f 100644
--- a/zruntime.S
+++ b/zruntime.S
@@ -150,7 +150,15 @@ z80_read_ym2612:
 	call z80_save_context
 	mov %r13w, %di
 	push %rsi
+	test $8, %rsp
+	jnz 0f
 	call z80_read_ym
+	jmp 1f
+0:
+	sub $8, %rsp
+	call z80_read_ym
+	add $8, %rsp
+1:
 	pop %rsi
 	mov %al, %r13b
 	call z80_load_context
@@ -196,7 +204,15 @@ z80_write_ym2612:
 	call z80_save_context
 	mov %r14w, %di
 	mov %r13b, %dl
+	test $8, %rsp
+	jnz 0f
+	call z80_write_ym
+	jmp 1f
+0:
+	sub $8, %rsp
 	call z80_write_ym
+	add $8, %rsp
+1:
 	mov %rax, %rsi
 	jmp z80_load_context
 z80_write_bank_reg:
@@ -219,7 +235,15 @@ z80_write_vdp:
 	call z80_save_context
 	mov %r14w, %di
 	mov %r13b, %dl
+	test $8, %rsp
+	jnz 0f
+	call z80_vdp_port_write
+	jmp 1f
+0:
+	sub $8, %rsp
 	call z80_vdp_port_write
+	add $8, %rsp
+1:
 	mov %rax, %rsi
 	jmp z80_load_context
 
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