From 119bf0615e0d6f96e5b3c79f1be83c5c41816cad Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 2 Feb 2015 22:29:44 +0000
Subject: [PATCH] lowlevel-z80: support the experimental entry optimisation

---
 Kernel/lowlevel-z80.s | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Kernel/lowlevel-z80.s b/Kernel/lowlevel-z80.s
index c923d5eb..5037bbb9 100644
--- a/Kernel/lowlevel-z80.s
+++ b/Kernel/lowlevel-z80.s
@@ -546,3 +546,30 @@ numeral:add a, #0x30 ; start at '0' (0x30='0')
 .else
 	.include "lowlevel-z80-cmos.s"
 .endif
+
+;
+;	These are needed by the experimental SDCC size optimisations
+;
+
+	.globl __enter, __enter_s
+
+__enter:
+	pop hl		; return address
+	push ix		; save frame pointer
+	ld ix, #0
+	add ix, sp	; set ix to the stack frame
+	jp (hl)		; and return
+
+__enter_s:
+	pop hl		; return address
+	push ix		; save frame pointer
+	ld ix, #0
+	add ix, sp	; frame pointer
+	ld e, (hl)	; size byte
+	ld d, #0xFF	; always minus something..
+	inc hl
+	ex de, hl
+	add hl, sp
+	ld sp, hl
+	push de
+	ret
-- 
2.34.1