crc/retroforth
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
retroforth/doc/html/chapters/internals/io-devices.html
crc e89789839b rebuild .html documentation; correct a filename reference (Rx.md -> image/retro.muri) reported by Martin Hohmann-Marriott 
FossilOrigin-Name: 429b138d84f0284a5f7054165c02a40f33ecbe919165eebc5271a07a367864bc
2022-06-03 10:41:52 +00:00

230 lines
14 KiB
HTML
Raw Blame History

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head>
<title>.</title>
<style type="text/css">
* { color: #000; background: #fff; max-width: 700px; }
tt, pre { background: #dedede; color: #111; font-family: monospace;
white-space: pre; display: block; width: 100%; }
.indentedcode { margin-left: 2em; margin-right: 2em; }
.codeblock {
background: #dedede; color: #111; font-family: monospace;
box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
padding: 7px;
display: block;
}
.indentedlist { margin-left: 2em; color: #000; }
span { white-space: pre; }
.text { color: #000; white-space: pre; background: #dedede; }
.colon { color: #000; background: #dedede; }
.note { color: #000; background: #dedede; }
.str { color: #000; text-decoration: underline; background: #dedede; }
.num { color: #000; background: #dedede; font-weight: bold; font-style: italic; }
.fnum { color: #000; font-weight: bold; background: #dedede; }
.ptr { color: #000; font-weight: bold; background: #dedede; }
.fetch { color: #000; font-style: italic; background: #dedede; }
.store { color: #000; font-style: italic; background: #dedede; }
.char { color: #000; background: #dedede; }
.inst { color: #000; background: #dedede; }
.defer { color: #000; background: #dedede; }
.imm { color: #000; font-weight: bold; background: #dedede; }
.prim { color: #000; font-weight: bolder; background: #dedede; }
.tt { white-space: pre; font-family: monospace; background: #dedede; }
.h1, .h2, .h3, .h4 { white-space: normal; }
.h1 { font-size: 125%; }
.h2 { font-size: 120%; }
.h3 { font-size: 115%; }
.h4 { font-size: 110%; }
.hr { display: block; height: 2px; background: #000000; }
</style>
</head><body>
<p><br/><br/>
I/O devices on Nga are exposed via three instructions:
<br/><br/>
<tt class='indentedcode'>ie&nbsp;&nbsp;enumerate&nbsp;i/o&nbsp;devices</tt>
<tt class='indentedcode'>iq&nbsp;&nbsp;query&nbsp;i/o&nbsp;device&nbsp;for&nbsp;class&nbsp;and&nbsp;version</tt>
<tt class='indentedcode'>ii&nbsp;&nbsp;invoke&nbsp;i/o&nbsp;interaction</tt>
<br/><br/>
All devices are registered with the VM. How this occurs is
implementation dependent.
<br/><br/>
<br/><br/>
Use the <span class="tt">ie</span> instruction to return the number of attached devices.
<br/><br/>
<tt class='indentedcode'>i&nbsp;ie......</tt>
<br/><br/>
Upon running, the stack will contain the number of devices. You
can then query these by passing the device number to <span class="tt">iq</span>.
<br/><br/>
<br/><br/>
Use <span class="tt">iq</span> to query an attached device. This will return two values,
a device class and a revision number.
<br/><br/>
The device class will be the top value on the stack.
<br/><br/>
<br/><br/>
You can trigger an I/O operation by passing the device handle to
the <span class="tt">ii</span> instruction.
<br/><br/>
E.g., to display a character (ASCII code 98 in this case):
<br/><br/>
<tt class='indentedcode'>i&nbsp;liliii..</tt>
<tt class='indentedcode'>d&nbsp;98</tt>
<tt class='indentedcode'>d&nbsp;0</tt>
<br/><br/>
Be sure to pass the device handle, not the device class.
<br/><br/>
<br/><br/>
Ultimately devices are implementation-specific, but the
standard system provides or reserves the following:
<br/><br/>
<tt class='indentedcode'>&nbsp;ID&nbsp;&nbsp;|&nbsp;Device&nbsp;Class&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Notes&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>-----+------------------+----------------------------+</tt>
<tt class='indentedcode'>0000&nbsp;|&nbsp;Generic&nbsp;Output&nbsp;&nbsp;&nbsp;|&nbsp;Always&nbsp;present&nbsp;as&nbsp;handle&nbsp;0&nbsp;|</tt>
<tt class='indentedcode'>0001&nbsp;|&nbsp;Keyboard&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0002&nbsp;|&nbsp;Floating&nbsp;Point&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0003&nbsp;|&nbsp;Block&nbsp;Storage&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Raw,&nbsp;1024&nbsp;cell&nbsp;blocks&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0004&nbsp;|&nbsp;Filesystem&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Unix-style&nbsp;Files&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0005&nbsp;|&nbsp;Clock&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0006&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0007&nbsp;|&nbsp;Network:&nbsp;Sockets&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0008&nbsp;|&nbsp;Syscalls:&nbsp;Unix&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0009&nbsp;|&nbsp;Scripting&nbsp;Hooks&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>0010&nbsp;|&nbsp;Random&nbsp;Number&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>1000&nbsp;|&nbsp;Image&nbsp;Saving&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<br/><br/>
It must be noted here that nothing forces devices to use these
class identifiers, and one must take care to use an Nga
implementation that provides the devices they need.
<br/><br/>
<br/><br/>
Over time, the functionality a device provides may change. To allow
detection of this, the query functionality provides a revision number.
Your code can use this to ensure that the device provided supports
the level of functionality you need.
<br/><br/>
<br/><br/>
<br/><br/>
Supported by all Nga implementations. This is required to be the
first device, and is the only one guaranteed to be provided. It
consumes a value from the stack, writing to to the host-specific
output. (This does not need to be a screen).
<br/><br/>
<br/><br/>
Read and return a keypress.
<br/><br/>
Consumes no data, returns a single value representing the
character that was read.
<br/><br/>
No subcommands are defined.
<br/><br/>
<br/><br/>
The current revision is 1.
<br/><br/>
It currently provides:
<br/><br/>
<tt class='indentedcode'>n:to-float&nbsp;&nbsp;(n-_f:-n)</tt>
<tt class='indentedcode'>s:to-float&nbsp;&nbsp;(s-_f:-n)</tt>
<tt class='indentedcode'>f:to-number&nbsp;(f:a-__-n)</tt>
<tt class='indentedcode'>f:to-string&nbsp;(f:n-__-s)</tt>
<tt class='indentedcode'>f:+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:*&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:/&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:floor&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:ceiling&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:sqrt&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:eq?&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:-eq?&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:lt?&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:gt?&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:depth&nbsp;(-n)</tt>
<tt class='indentedcode'>f:dup&nbsp;&nbsp;&nbsp;(f:a-aa)</tt>
<tt class='indentedcode'>f:drop&nbsp;&nbsp;(f:a-)</tt>
<tt class='indentedcode'>f:swap&nbsp;&nbsp;(f:ab-ba)</tt>
<tt class='indentedcode'>f:log&nbsp;&nbsp;&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:power&nbsp;(f:ab-c)</tt>
<tt class='indentedcode'>f:sin&nbsp;&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:cos&nbsp;&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:tan&nbsp;&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:asin&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:acos&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:atan&nbsp;&nbsp;(f:f-f)</tt>
<tt class='indentedcode'>f:push&nbsp;&nbsp;(f:f-)</tt>
<tt class='indentedcode'>f:pop&nbsp;&nbsp;&nbsp;(f:-f)</tt>
<tt class='indentedcode'>f:adepth&nbsp;&nbsp;(-n)</tt>
<br/><br/>
<br/><br/>
Reserved for future use.
<br/><br/>
<br/><br/>
Currently at revision 0.
<br/><br/>
This implements a device providing traditional Unix-like files.
<br/><br/>
Takes a value indicating an operation, and each operation takes
additional values.
<br/><br/>
<tt class='indentedcode'>|&nbsp;Operation&nbsp;|&nbsp;Stack&nbsp;|&nbsp;Action&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;---------&nbsp;|&nbsp;-----&nbsp;|&nbsp;--------------------------------&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;sm-h&nbsp;&nbsp;|&nbsp;Open&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;h-&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Close&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;h-c&nbsp;&nbsp;&nbsp;|&nbsp;Read&nbsp;a&nbsp;byte&nbsp;from&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;3&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;ch-&nbsp;&nbsp;&nbsp;|&nbsp;Write&nbsp;a&nbsp;byte&nbsp;to&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;4&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;h-n&nbsp;&nbsp;&nbsp;|&nbsp;Return&nbsp;current&nbsp;pointer&nbsp;into&nbsp;file&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;5&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;nh-&nbsp;&nbsp;&nbsp;|&nbsp;Move&nbsp;pointer&nbsp;in&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;6&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;h-n&nbsp;&nbsp;&nbsp;|&nbsp;Return&nbsp;the&nbsp;size&nbsp;of&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;7&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;s-&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Delete&nbsp;a&nbsp;file&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<tt class='indentedcode'>|&nbsp;8&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;h-&nbsp;&nbsp;&nbsp;&nbsp;|&nbsp;Flush&nbsp;pending&nbsp;writes&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;|</tt>
<br/><br/>
<br/><br/>
This is currently at revision 0.
<br/><br/>
On invocation, this returns a random number.
<br/><br/>
<br/><br/>
On the C implementation, each I/O device has the needed support
functions defined, then a query function and invocation function
defined.
<br/><br/>
As an example, to add a device that has two functions, I might do:
<br/><br/>
<tt class='indentedcode'>void&nbsp;one()&nbsp;{</tt>
<tt class='indentedcode'>&nbsp;&nbsp;stack_push(100);</tt>
<tt class='indentedcode'>}</tt>
<br/><br/>
<tt class='indentedcode'>void&nbsp;two()&nbsp;{</tt>
<tt class='indentedcode'>&nbsp;&nbsp;stack_push(200);</tt>
<tt class='indentedcode'>}</tt>
<br/><br/>
<tt class='indentedcode'>Handler&nbsp;device_actions[]&nbsp;=&nbsp;{</tt>
<tt class='indentedcode'>&nbsp;&nbsp;one,&nbsp;two</tt>
<tt class='indentedcode'>}</tt>
<br/><br/>
<tt class='indentedcode'>void&nbsp;io_device()&nbsp;{</tt>
<tt class='indentedcode'>&nbsp;&nbsp;device_actions[stack_pop()]();</tt>
<tt class='indentedcode'>}</tt>
<br/><br/>
<tt class='indentedcode'>void&nbsp;query_device()&nbsp;{</tt>
<tt class='indentedcode'>&nbsp;&nbsp;stack_push(0);&nbsp;&nbsp;&nbsp;&nbsp;/*&nbsp;Revision&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*/</tt>
<tt class='indentedcode'>&nbsp;&nbsp;stack_push(1234);&nbsp;/*&nbsp;Device&nbsp;Class&nbsp;*/</tt>
<tt class='indentedcode'>}</tt>
<br/><br/>
Then add pointers to <span class="tt">io_device</span> to <span class="tt">IO_deviceHandlers</span> and
<span class="tt">query_device</span> to <span class="tt">IO_queryHandlers</span> and increase the <span class="tt">NUM_DEVICES</span>
by one.
<br/><br/>
You will then need to write a set of Retro words to use the new
device.
<br/><br/>
<tt class='indentedcode'>:device:one&nbsp;#1&nbsp;#1234&nbsp;io:scan-for&nbsp;io:invoke&nbsp;;</tt>
<tt class='indentedcode'>:device:two&nbsp;#2&nbsp;#1234&nbsp;io:scan-for&nbsp;io:invoke&nbsp;;</tt>
<br/><br/>
Rebuild the VM, adding these to image.
</p>
</body></html>
Reference in a new issue View git blame Copy permalink