From d024340a72370e3777f0fc3fa98dce8356b4a6fe Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Tue, 31 Mar 2015 22:48:18 +0100
Subject: [PATCH] z80: add in and out operators

(Not yet tested)
---
 Kernel/cpu-z80/cpu.h         |  2 ++
 Kernel/lowlevel-z80-banked.s | 24 ++++++++++++++++++++++++
 Kernel/lowlevel-z80.s        | 20 ++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/Kernel/cpu-z80/cpu.h b/Kernel/cpu-z80/cpu.h
index 77c38934..3769db0c 100644
--- a/Kernel/cpu-z80/cpu.h
+++ b/Kernel/cpu-z80/cpu.h
@@ -17,6 +17,8 @@ typedef uint16_t irqflags_t;
 
 extern irqflags_t di(void);
 extern void irqrestore(irqflags_t f);
+extern void out(uint8_t addr, uint8_t val);
+extern uint8_t in(uint8_t addr);
 
 /* Z80 binaries start with a JP */
 #define EMAGIC    0xc3    /* Header of executable */
diff --git a/Kernel/lowlevel-z80-banked.s b/Kernel/lowlevel-z80-banked.s
index 25257d7e..992e75a0 100644
--- a/Kernel/lowlevel-z80-banked.s
+++ b/Kernel/lowlevel-z80-banked.s
@@ -44,6 +44,8 @@
 	.globl interrupt_handler
 	.globl _di
 	.globl _irqrestore
+	.globl _in
+	.globl _out
 
         ; imported symbols
         .globl _trap_monitor
@@ -546,6 +548,28 @@ outnibble:
         add a, #0x07 ; start at 'A' (10+7+0x30=0x41='A')
 numeral:add a, #0x30 ; start at '0' (0x30='0')
         jp outchar
+;
+;	I/O helpers for cases we don't use __sfr
+;
+_out:
+	pop hl
+	pop de
+	pop bc
+	out (c), b
+	push bc
+	push de
+	jp (hl)
+
+_in:
+	pop hl
+	pop de
+	pop bc
+	push bc
+	push de
+	push hl
+	in l, (c)
+	ret
+
 
 ;
 ;	Pull in the CPU specific workarounds
diff --git a/Kernel/lowlevel-z80.s b/Kernel/lowlevel-z80.s
index 5037bbb9..f8a9b47c 100644
--- a/Kernel/lowlevel-z80.s
+++ b/Kernel/lowlevel-z80.s
@@ -44,6 +44,8 @@
 	.globl interrupt_handler
 	.globl _di
 	.globl _irqrestore
+	.globl _out
+	.globl _in
 
         ; imported symbols
         .globl _trap_monitor
@@ -537,6 +539,24 @@ outnibble:
 numeral:add a, #0x30 ; start at '0' (0x30='0')
         jp outchar
 
+;
+;	I/O helpers for cases we don't use __sfr
+;
+_out:
+	pop hl
+	pop bc
+	out (c), b
+	push bc
+	jp (hl)
+
+_in:
+	pop hl
+	pop bc
+	push bc
+	push hl
+	in l, (c)
+	ret
+
 ;
 ;	Pull in the CPU specific workarounds
 ;
-- 
2.34.1