From f6f9467cd1d22586ff4c0cc9d67938c0603a8c7c Mon Sep 17 00:00:00 2001
From: patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>
Date: Sat, 23 Feb 2008 14:26:46 +0000
Subject: [PATCH] Incorporate patch 1899525

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@720 42af7a65-404d-4744-a932-0658087f49c3
---
 arch/z80/src/Makefile       |  1 +
 arch/z80/src/Makefile.sdcc  |  2 +-
 arch/z80/src/z80/Make.defs  |  2 ++
 arch/z80/src/z80/README.txt | 49 +++++++++++++++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 arch/z80/src/z80/README.txt

diff --git a/arch/z80/src/Makefile b/arch/z80/src/Makefile
index 39c5697837..6cc1463d0f 100644
--- a/arch/z80/src/Makefile
+++ b/arch/z80/src/Makefile
@@ -38,6 +38,7 @@
 
 -include $(TOPDIR)/Make.defs
 -include chip/Make.defs
+-include board/Make.defs
 
 ############################################################################
 # Compiler-Dependent Make
diff --git a/arch/z80/src/Makefile.sdcc b/arch/z80/src/Makefile.sdcc
index 895ecc4bae..8865ad4b99 100644
--- a/arch/z80/src/Makefile.sdcc
+++ b/arch/z80/src/Makefile.sdcc
@@ -71,7 +71,7 @@ DEPSRCS		= $(CSRCS)
 ARCH_SRCDIR	= $(TOPDIR)/arch/$(CONFIG_ARCH)/src
 BOARDDIR	= $(TOPDIR)/arch/$(CONFIG_ARCH)/src/board
 
-VPATH		= chip:common
+VPATH		= chip:common:board
 
 # Libraries
 
diff --git a/arch/z80/src/z80/Make.defs b/arch/z80/src/z80/Make.defs
index 76b98199a2..01564f059a 100644
--- a/arch/z80/src/z80/Make.defs
+++ b/arch/z80/src/z80/Make.defs
@@ -33,11 +33,13 @@
 #
 ############################################################################
 
+ifeq ($(CONFIG_ARCH_HAVEHEAD),)
 ifeq ($(CONFIG_LINKER_ROM_AT_0000),y)
 HEAD_ASRC	= z80_rom.asm
 else
 HEAD_ASRC	= z80_head.asm
 endif
+endif
 
 CMN_ASRCS	= 
 CMN_CSRCS	= up_initialize.c up_allocateheap.c up_createstack.c \
diff --git a/arch/z80/src/z80/README.txt b/arch/z80/src/z80/README.txt
new file mode 100644
index 0000000000..81cdf756d0
--- /dev/null
+++ b/arch/z80/src/z80/README.txt
@@ -0,0 +1,49 @@
+arch/z80/src/z80
+^^^^^^^^^^^^^^^^
+
+The arch/z80 directories contain files to support a variety of 8-bit architectures
+from ZiLOG (and spin-architectures such as the Rabbit2000).  The arch/z80/src/z80
+sub-directory contains logic unique to the classic Z80 chip.
+
+Files in this directory include:
+
+z80_head.asm
+	This is the main entry point into the Z80 program.  This includes the
+	handler for the RESET, power-up interrupt vector and address zero and all
+	RST interrupts.
+
+z80_rom.asm
+	Some architectures may hae ROM located at address zero.  In this case, a
+	special version of the "head" logic must be used.  This specail "head"
+	file is probably board-specific and, hence, belongs in the board-specific
+	configs/<board-name>/src directory.  This file may, however, be used as
+	a model for such a board-specific file.
+
+	z80_rom.S is enabled by specifying CONFIG_LINKER_ROM_AT_0000 in the
+	configuration file.
+
+	A board specific version in the configs/<board-name>/src directory can be
+	used by:
+	
+	1. Define CONFIG_ARCH_HAVEHEAD
+	2. Add the board-specific head file, say <filename>.asm, to
+	   configs/<board-name>/src
+	3. Add a file called Make.defs in the configs/<board-name>/src directory
+	   containing the line:  HEAD_ASRC = <file-name>.asm
+
+Make.defs
+	This is the standard makefile fragment that must be provided in all
+	chip directories.  This fragment identifies the chip-specific file to
+	be used in building libarch.
+
+chip.h
+	This is the standard header file that must be provided in all chip
+	directories.
+
+z80_initialstate.c, z80_copystate.c,  z80_restoreusercontext.asm, and
+z80_saveusercontext.asm, switch
+ 	These files implement the Z80 context switching logic
+
+z80_schedulesigaction.c and  z80_sigdeliver.c
+	These files implement Z80 signal handling.
+ 
\ No newline at end of file