some more tweaking, added docs page

doc/index.sgml

@@ -137,6 +137,9 @@
   <tag><htmlurl url="osi.html" name="osi.html"></tag>
   Topics specific to the Ohio Scientific machines.
 
+  <tag><htmlurl url="pce.html" name="pce.html"></tag>
+  Topics specific to NEC PC-Engine (TurboGrafx) Console.
+
   <tag><htmlurl url="pet.html" name="pet.html"></tag>
   Topics specific to the Commodore PET machines.
 

doc/pce.sgml

@@ -0,0 +1,198 @@
+<!doctype linuxdoc system>
+
+<article>
+
+<title>PC-Engine (TurboGrafx) System specific information for cc65
+<author>
+<url url="mailto:groepaz@gmx.net" name="Groepaz/Hitmen">
+<date>2015-07-14
+
+<abstract>
+An overview over the PCE runtime system as it is implemented for the
+cc65 C compiler.
+</abstract>
+
+<!-- Table of contents -->
+<toc>
+
+<!-- Begin the document -->
+
+<sect>Overview<p>
+
+This file contains an overview of the PCE runtime system as it comes
+with the cc65 C compiler. It describes the memory layout, PCE specific header
+files, available drivers, and any pitfalls specific to that platform.
+
+Please note that PCE specific functions are just mentioned here, they are
+described in detail in the separate <url url="funcref.html" name="function
+reference">. Even functions marked as "platform dependent" may be available on
+more than one platform. Please see the function reference for more
+information.
+
+
+<sect>Binary format<p>
+
+The standard binary output format generated by the linker for the PCE target
+is a cartridge image with no header. It is of course possible to change this
+behaviour by using a modified startup file and linker config.
+
+<sect>Memory layout<p>
+
+cc65 generated programs with the default setup run with the I/O area and a
+CHR bank enabled, which gives a usable memory range of &dollar;8000 - &dollar;FFF3.
+All boot ROM entry points may be called directly without additional code.
+
+Special locations:
+
+<descrip>
+  <tag/Text screen and Font/
+  The text screen is located at VRAM &dollar;0000,
+  the Font is located at VRAM &dollar;2000.
+
+  <tag/Stack/
+  The C runtime stack is located in system RAM at &dollar;3FFF and growing downwards.
+
+  <tag/BSS and Data/
+
+  The BSS (uninitialized variables) and Data (initialized variables) sections are
+  placed one after the other into system RAM at &dollar;2000.
+
+  <tag/Heap/
+  The C heap is located after the end of the Data section and grows towards the C
+  runtime stack.
+
+  <tag/Code/
+  The startup code is located at &dollar;E000 in the System/Hardware bank. Further
+  code can be placed in other ROM banks, this must be done manually however.
+
+</descrip><p>
+
+
+
+<sect>Platform specific header files<p>
+
+Programs containing PCE specific code may use the <tt/pce.h/ header file.
+
+
+<sect1>PCE specific functions<p>
+
+<itemize>
+<item>waitvblank
+<item>get_tv
+</itemize>
+
+
+
+<sect1>Hardware access<p>
+
+The following pseudo variables declared in the <tt/pce.inc/ include file do
+allow access to hardware located in the address space.
+
+<descrip>
+
+  <tag><tt/PSG/</tag>
+  The <tt/PSG/ defines allow access to the PSG chip (Programmable Sound Generator).
+
+  <tag><tt/VCE/</tag>
+  The <tt/VCE/ defines allow access to the VCE chip (Video Color Encoder).
+
+  <tag><tt/VDC/</tag>
+  The <tt/VDC/ defines allow access to the VDC chip (Video Display Controller).
+
+</descrip><p>
+
+
+
+<sect>Loadable drivers<p>
+
+All drivers must be statically linked because no file I/O is available.
+The names in the parentheses denote the symbols to be used for static linking of the drivers.
+
+
+<sect1>Graphics drivers<p>
+
+<descrip>
+
+No TGI graphics drivers are currently available for the PCE.
+
+</descrip><p>
+
+
+<sect1>Extended memory drivers<p>
+
+No extended memory drivers are currently available for the PCE.
+
+
+<sect1>Joystick drivers<p>
+
+<descrip>
+
+  <tag><tt/pce-stdjoy.joy (pce_stdjoy)/</tag>
+  A joystick driver for the standard two buttons joypad is available.
+
+</descrip><p>
+
+
+<sect1>Mouse drivers<p>
+
+No mouse drivers are currently available for the PCE.
+
+
+<sect1>RS232 device drivers<p>
+
+No serial drivers are currently available for the PCE.
+
+
+
+<sect>Limitations<p>
+
+<sect1>Disk I/O<p>
+
+The existing library for the PCE doesn't implement C file
+I/O. There are no hacks for the <tt/read()/ and <tt/write()/ routines.
+
+To be more concrete, this limitation means that you cannot use any of the
+following functions (and a few others):
+
+<itemize>
+<item>fclose
+<item>fopen
+<item>fread
+<item>fprintf
+<item>fputc
+<item>fscanf
+<item>fwrite
+<item>...
+</itemize>
+
+
+
+<sect>Other hints<p>
+
+
+
+<sect>License<p>
+
+This software is provided 'as-is', without any expressed or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+<enum>
+<item>	The origin of this software must not be misrepresented; you must not
+	claim that you wrote the original software. If you use this software
+	in a product, an acknowledgment in the product documentation would be
+	appreciated but is not required.
+<item>	Altered source versions must be plainly marked as such, and must not
+	be misrepresented as being the original software.
+<item>	This notice may not be removed or altered from any source
+	distribution.
+</enum>
+
+</article>
+
+
+