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Fixed some stale links in the previous blog post

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Jeff Parsons 2016-10-23 09:09:44 -07:00 • committed by Jeff Parsons
commit a3e0e19e95
1 changed files with 12 additions and 17 deletions
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29
_posts/2016-10-06-introducing-pdpjs-a-pdp-11-emulator.md
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@ -15,8 +15,7 @@ machines:
connection: serialPort->test1170.dl11
---
[PDPjs](http://www.pcjs.org/devices/pdp11/machine/) is the newest addition to the PCjs family of emulators, joining
PCx86, PC8080, and C1Pjs.
[PDPjs](/devices/pdp11/machine/) is the newest addition to the PCjs family of emulators, joining PCx86, PC8080, and C1Pjs.
While PDPjs may eventually support a range of DEC PDP machines, my current focus is on the PDP-11, starting with the
PDP-11/70. From there, I'll work backwards to support other PDP-11 models, such as the PDP-11/45, until I reach the
@ -28,24 +27,20 @@ JavaScript [PDP 11/70 Emulator (v1.3)](http://skn.noip.me/pdp11/pdp11.html) writ
Since his emulator is a fully functional 11/70, it made sense to start there and work backwards, neutering features
as needed.
The code has already undergone a lot of refactoring. Opcodes are now decoded by function table rather than one
large switch statement, and every opcode is implemented with a discrete function. Other refactoring includes
flag management, interrupt management, and device management.
The code has already undergone a lot of refactoring. Opcodes are now decoded by function tables rather than a single
switch statement, and every opcode is implemented with a discrete function. Other refactoring includes flag management,
interrupt management, and device management.
Most of the work remaining is in device management. Like other PCjs emulators, PDPjs now has a Bus component,
[bus.js](https://github.com/jeffpar/pcjs/blob/master/modules/pdp11/lib/bus.js), that allows separate device components
to register I/O handlers for specific UNIBUS addresses. During the initial port, I moved all of Paul's original device
management code into one "catch-all" component,
[device.js](https://github.com/jeffpar/pcjs/blob/master/modules/pdp11/lib/device.js), which must now be converted
to the new I/O registration model.
Most of the work remaining is in device management. Like other PCjs emulators, PDPjs has a Bus component,
[bus.js](/modules/pdp11/lib/bus.js), that allows separate device components to register I/O handlers for specific
UNIBUS addresses. During the initial port, I moved all of Paul's original device management code into one "catch-all"
component, [device.js](/modules/pdp11/lib/device.js), which has now been converted to the new I/O registration model.
The first new device component is
[serialport.js](https://github.com/jeffpar/pcjs/blob/master/modules/pdp11/lib/serialport.js), which is currently the
The first new device component is [serialport.js](/modules/pdp11/lib/serialport.js), which is currently the
only means PDPjs has of communicating with the outside world. So you can try
[PDPjs connected to a VT100 Terminal](http://www.pcjs.org/devices/pdp11/machine/1170/vt100/), by clicking the "Run"
button on the test machine. The test machine is running
[custom boot code](https://github.com/jeffpar/pcjs/blob/master/apps/pdp11/boot/test/BOOTTEST.mac), adapted from boot code
written by Paul, but due to the lack of other device support, nothing can be booted yet.
[PDPjs connected to a VT100 Terminal](/devices/pdp11/machine/1170/vt100/), by clicking the "Run" button on the test machine.
The test machine is running [custom boot code](/apps/pdp11/boot/test/), adapted from boot code written by Paul, but due to the
lack of other device support, nothing can be booted yet.
Obviously PDPjs is very much a work-in-progress. Before I proceed much farther, I really want to put the CPU through
some rigorous testing, so I'll be on the lookout for some comprehensive PDP-11 instruction tests. Or I'll write my own,