Lots of tweaks in advance of PDPjs support for loading tape files

apps/pdp11/boot/bootstrap/BOOTSTRAP-16KB.json

@@ -0,0 +1,4 @@
+{"load":0x3FE4,"exec":0x3FE4,"words":[
+0x1DC1 /*016701*/,0x0016 /*000026*/,0x15C2 /*012702*/,0x00EA /*000352*/,0x0A89 /*005211*/,0x8BC9 /*105711*/,0x80FE /*100376*/,0x9C72 /*116162*/,
+0x0002 /*000002*/,0x3F00 /*037400*/,0x0AB7 /*005267*/,0xFFEE /*177756*/,0x01F5 /*000765*/,0xFF68 /*177550*/]
+}

apps/pdp11/boot/bootstrap/BOOTSTRAP-16KB.lst

@@ -0,0 +1,9 @@
+037744: 016701 000026          MOV   26(PC),R1              ; @037776
+037750: 012702 000352          MOV   #352,R2
+037754: 005211                 INC   @R1
+037756: 105711                 TSTB  @R1
+037760: 100376                 BPL   037756
+037762: 116162 000002 037400   MOVB  2(R1),37400(R2)
+037770: 005267 177756          INC   177756(PC)             ; @037752
+037774: 000765                 BR    037750
+037776: 177550                 .WORD 177550

apps/pdp11/boot/bootstrap/README.md

@@ -0,0 +1,56 @@
+---
+layout: page
+title: PDP-11 Bootstrap Loader
+permalink: /apps/pdp11/boot/bootstrap/
+---
+
+PDP-11 Bootstrap Loader
+-----------------------
+
+The blog post "[PDP-11 Paper Tape BASIC](http://www.avitech.com.au/ptb/ptb.html)" describes the *Bootstrap Loader*,
+a small program used to load the *Absolute Loader*, which in turn loads the *PDP-11 BASIC Paper Tape*. 
+ 
+Here's what the *Bootstrap Loader* looks like:
+
+	Location  Instruction
+	 037744     016701
+	 037746     000026
+	 037750     012702
+	 037752     000352
+	 037754     005211
+	 037756     105711
+	 037760     100376
+	 037762     116162
+	 037764     000002
+	 037766     037400
+	 037770     005267
+	 037772     177756
+	 037774     000765
+	 037776     177550
+
+Using a [PDPjs](/modules/pdpjs/) machine such as the [PDP-11/20 Test Machine with Debugger](/devices/pdp11/machine/1120/test/debugger/),
+the *Bootstrap Loader* is easily entered with a single Debugger "edit" command:
+
+	e 037744 016701 000026 012702 000352 005211 105711 100376 116162 000002 037400 005267 177756 000765 177550
+
+You can immediately disassemble the code using `u 037744 040000`:
+
+	037744: 016701 000026          MOV   26(PC),R1              ; @037776
+	037750: 012702 000352          MOV   #352,R2
+	037754: 005211                 INC   @R1
+	037756: 105711                 TSTB  @R1
+	037760: 100376                 BPL   037756
+	037762: 116162 000002 037400   MOVB  2(R1),37400(R2)
+	037770: 005267 177756          INC   177756(PC)             ; @037752
+	037774: 000765                 BR    037750
+	037776: 177550                 .WORD 177550
+
+I also pasted the disassembled code into a listing file, [BOOTSTRAP-16KB.LST](BOOTSTRAP-16KB.lst), and ran [FileDump](/modules/filedump)
+to produce a [BOOTSTRAP-16KB.JSON](BOOTSTRAP-16KB.json) that can be pre-loaded into any machine:
+
+	filedump --file=BOOTSTRAP-16KB.lst --format=octal --output=BOOTSTRAP-16KB.json
+
+To run the *Bootstrap Loader*, set the PC to 037744 and start the machine: 
+
+	r pc=037744
+	g