1 <!doctype linuxdoc system>
5 <title>Ohio Scientific-specific information for cc65
7 <url url="mailto:stephan.muehlstrasser@web.de" name="Stephan Mühlstrasser">,<newline>
8 <url url="mailto:greg.king5@verizon.net" name="Greg King">
12 An overview over the Ohio Scientific runtime system as it is implemented for the cc65 C
16 <!-- Table of contents -->
19 <!-- Begin the document -->
23 This file contains an overview of the Ohio Scientific runtime system as it comes with the
24 cc65 C compiler. It describes the memory layout, Ohio Scientific-specific header files,
25 and any pitfalls specific to that platform.
27 Please note that Ohio Scientific-specific functions are just mentioned here, they are
28 described in detail in the separate <url url="funcref.html" name="function
29 reference">. Even functions marked as "platform dependent" may be available on
30 more than one platform. Please see the function reference for more
35 Currently the target "osic1p" is implemented. This works for the Ohio Scientific
36 Challenger 1P machine and for the Briel Superboard /// replica.
38 <sect>Program file formats<p>
41 <tag/Binary, then text/
42 The standard binary output format generated by the linker for the osic1p
43 target is a pure machine language program.
45 For uploading into a real machine over its serial port or into an emulator,
46 that program must be converted into a text file that can be understood by
47 the 65V PROM monitor. For that purpose, the <bf/srec_cat/ program from <url
48 url="http://srecord.sourceforge.net/" name="the SRecord tool collection">
51 Care must be taken that the <tt/-offset/ and <tt/-execution-start-address/
52 options for the <bf/srec_cat/ program correspond to the start address
55 Example for converting an executable "hello" file that was built for the
56 default start address $0200 to an uploadable file "hello.c1p":
59 srec_cat hello -bin -of 0x200 -o hello.c1p -os -esa=0x200
63 The linker can create an alternate format that contains two parts:
65 <item>A text header that is understood by the 65V PROM monitor.
66 It is a boot loader that reads the second part.
67 <item>The default binary code that is described above.
70 You can make the alternate format by adding the option <tt/-u __BOOT__/ to
71 <tt/cl65/'s or <tt/ld65/'s command lines.
73 This format doesn't need to be converted. It is smaller than the text-only
74 format. But, it cannot be loaded by <url
75 url="http://www.pcjs.org/docs/c1pjs/" name="C1Pjs">; you must use the
76 SRecord-produced text-only format with that emulator. (However, if you know
77 that you never will use C1Pjs, then you can edit the
78 <tt>cfg/osic1p*.cfg</tt> files; uncomment the lines that import <tt/__BOOT__/.
79 Then, you won't need to use <tt/-u __BOOT__/ on your command lines.)
83 <sect>Memory layout<p>
85 By default programs compiled for the osic1p target are configured for 32 kB RAM.
86 The RAM size can be configured via the symbol <tt/__HIMEM__/.
91 <tag/Program start address/
92 The default start address is $0200. The start address is configurable
93 via the linker option <tt/--start-addr/.
96 The C runtime stack is located at the top of RAM and growing downwards.
97 The size is configurable via the symbol <tt/__STACKSIZE__/. The default
98 stack size is $0400.
101 The C heap is located at the end of the program and grows towards the C
105 The 1 kB video RAM is located at $D000. On the monitor, only a subset
106 of the available video RAM is visible. The address of the upper left corner
107 of the visible area is $D085 and corresponds to conio cursor
112 Example for building a program with start address $0300, stack size
113 $0200 and RAM size $2000:
116 cl65 --start-addr 0x300 -Wl -D,__HIMEM__=$2000,-D,__STACKSIZE__=$0200 -t osic1p hello.c
119 <sect>Linker configurations<p>
121 The ld65 linker comes with a default config file "osic1p.cfg" for the Ohio Scientific
122 Challenger 1P, which is implicitly used via <tt/-t osic1p/. The
123 osic1p package comes with additional secondary linker config files, which are
124 used via <tt/-t osic1p -C <configfile>/.
126 <sect1>Default config file (<tt/osic1p.cfg/)<p>
128 The default configuration is tailored to C programs.
130 <sect1><tt/osic1p-asm.cfg/<p>
132 This configuration is made for assembler programmers who don't need a special
135 To use this config file, assemble with <tt/-t osic1p/ and link with
136 <tt/-C osic1p-asm.cfg/. The former will make sure that correct runtime library
137 is used, while the latter supplies the actual config. When using <tt/cl65/,
138 use both command line options.
140 Sample command lines for <tt/cl65/:
143 cl65 -t osic1p -C osic1p-asm.cfg -o program source.s
144 cl65 -t osic1p -C osic1p-asm.cfg -u __BOOT__ -o program.lod source.s
147 <sect>Platform-specific header files<p>
149 Programs containing Ohio Scientific-specific code may use the <tt/osic1p.h/
152 <sect1>Ohio Scientific-specific functions<p>
154 There are currently no special Ohio Scientific functions.
156 <sect1>Hardware access<p>
158 There is no specific support for direct hardware access.
160 <sect>Loadable drivers<p>
162 There are no loadable drivers available.
164 <sect>Support for different screen layouts<p>
166 By default the conio library uses a 24 columns by 24 lines screen layout
167 for the Challenger 1P, like under BASIC. In addition to that there is support
168 for other screen layouts with extra modules.
170 There is a module <tt/screen-c1p-24x24.o/ in the OSI-specific
171 cc65 runtime library that contains all conio functions that depend
172 on the screen layout. No further configuration is needed for using the
173 default screen layout of the Challenger 1P.
175 For other screen layouts additional versions of the screen module are
176 available. The linker finds these modules without further configuration
177 if they are specified on the compiler or linker command line. The
178 extra module then overrides the default module.
180 Sample <tt/cl65/ command line to override the default screen
181 module with the module <tt/osic1p-screen-s3-32x28.o/:
184 cl65 -o hello -t osic1p osic1p-screen-s3-32x28.o hello.c
187 Currently the following extra screen configuration modules are implemented:
190 <item><tt>osic1p-screen-s3-32x28.o</tt>: 32 columns by 28 lines mode
191 for Briel Superboard ///</item>
196 <sect1>stdio implementation<p>
198 There is no support for stdio at the moment.
202 <sect1>Passing arguments to the program<p>
204 There is currently no support for passing arguments to a program.
206 <sect1>Program return code<p>
208 The program return code currently has no effect. When the main() function
209 finishes, the boot prompt is shown again.
213 This software is provided 'as-is', without any expressed or implied
214 warranty. In no event will the authors be held liable for any damages
215 arising from the use of this software.
217 Permission is granted to anyone to use this software for any purpose,
218 including commercial applications, and to alter it and redistribute it
219 freely, subject to the following restrictions:
222 <item> The origin of this software must not be misrepresented; you must not
223 claim that you wrote the original software. If you use this software
224 in a product, an acknowledgment in the product documentation would be
225 appreciated but is not required.
226 <item> Altered source versions must be plainly marked as such, and must not
227 be misrepresented as being the original software.
228 <item> This notice may not be removed or altered from any source