From 35d3e99c06e0a51ef3b12bb257c46646fd967461 Mon Sep 17 00:00:00 2001
From: Jeff Parsons <Jeff@pcjs.org>
Date: Mon, 6 Apr 2015 16:25:48 -0700
Subject: [PATCH] Details regarding use of NDISASM

---
 .../pc/bios/compaq/deskpro386/1988-01-28.nasm |  8 +++++--
 devices/pc/bios/compaq/deskpro386/README.md   | 24 +++++++++++++++----
 modules/htmlout/lib/htmlout.js                |  1 +
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/devices/pc/bios/compaq/deskpro386/1988-01-28.nasm b/devices/pc/bios/compaq/deskpro386/1988-01-28.nasm
index 56ff69727..64e733fb4 100644
--- a/devices/pc/bios/compaq/deskpro386/1988-01-28.nasm
+++ b/devices/pc/bios/compaq/deskpro386/1988-01-28.nasm
@@ -1,3 +1,5 @@
+	org	0x8000
+
 	xchg	bh,bl			; 00008000  86FB  '..'
 	xor	bh,bh			; 00008002  32FF  '2.'
 	shl	bx,1			; 00008004  D1E3  '..'
@@ -10604,15 +10606,17 @@ xdfee:	lea	di,[si+0x10]		; 0000DFEE  8D7C10  '.|.'
 	db	0xFF			; 0000DFFE  FF  '.'
 	db	0xFF			; 0000DFFF  FF  '.'
 	jmp	short xe05e		; 0000E000  EB5C  '.\'
+
 	db	'AUTHORS CAB93GLB93RWS93DJC93NPB(C)Copyright COMPAQ Computer Corporation 1982,83,84,85,86'
 
 	sub	al,0xe9			; 0000E05A  2CE9  ',.'
 	dec	cx			; 0000E05C  49  'I'
 	db	0xDA			; 0000E05D  DA  '.'
 xe05e:	jmp	0xf000:0x8e31		; 0000E05E  EA318E00F0  '.1...'
-	db	'((CC))CCooppyyrriigghhtt  CCOOMMPPAAQQ  CCoommppuutteerr  CCoorrppoorraattiioonn  11998822,,8833,,8844,,8855,,8866,,8877--AAllll  rriigghhttss  rreesseerrvveedd..'
-	mov	al,0xd			; 0000E105  B00D  '.',0x0D  0x0D
 
+	db	'((CC))CCooppyyrriigghhtt  CCOOMMPPAAQQ  CCoommppuutteerr  CCoorrppoorraattiioonn  11998822,,8833,,8844,,8855,,8866,,8877--AAllll  rriigghhttss  rreesseerrvveedd..'
+
+	mov	al,0xd			; 0000E105  B00D  '.',0x0D  0x0D
 	out	0x84,al			; 0000E107  E684  '..'
 	mov	al,0x12			; 0000E109  B012  '..'
 	out	0x4b,al			; 0000E10B  E64B  '.K'
diff --git a/devices/pc/bios/compaq/deskpro386/README.md b/devices/pc/bios/compaq/deskpro386/README.md
index 708c09bc3..6bed0ee82 100644
--- a/devices/pc/bios/compaq/deskpro386/README.md
+++ b/devices/pc/bios/compaq/deskpro386/README.md
@@ -63,17 +63,33 @@ while the /PGM should be connected to INPUT HIGH VOLTAGE.  So I wired pin 27 (/P
 worked perfectly.  The NYC Resistor article implied that every *active low* pin should be connected to GND, but apparently
 there are exceptions to that general rule.
 
-Producing Source Code with NDISASM
+Producing BIOS Source Code
 ---
-From the current directory, I ran:
+In the current directory, I ran NDISASM (the disassembler included with NASM):
 
 	ndisasm -o0x8000 -se105h -se05ah -se6ffh -sf025h -sf8aah private/1988-01-28.rom > 1988-01-28.nasm
 
-Then I ran the TextOut command, with the *--nasm* option, to clean up the code:
+The `-o0x8000` argument is required to "org" the file at the proper starting address, but the `-s` arguments
+are optional; they simply establish a few sync points within the ROM image that save a little cleanup effort, by
+preventing disassembly in the middle of instructions.
+
+Then I ran the PCjs [TextOut](/modules/textout/lib/) command, with the *--nasm* option, to prepare the code for reassembly:
 
 	node ~/Sites/pcjs/modules/textout/bin/textout --file=1988-01-28.nasm --nasm > t.nasm
 	mv t.nasm 1988-01-28.nasm
 
-The result, [1988-01-28.nasm](1988-01-28.nasm), can then be reassembled:
+The result, [1988-01-28.nasm](1988-01-28.nasm), after a small amount of manual cleanup, can now be successfully reassembled:
 
 	nasm -f bin 1988-01-28.nasm -l 1988-01-28.lst -o 1988-01-28.rom
+
+However, it does NOT produce a binary identical to the original ROM, in part because of instruction ambiguities (ie,
+instructions that can be assembled multiple ways). 
+
+It's possible that reassembled ROM may still work, but more research is required.
+
+One interesting section of the Compaq DeskPro ROM is this string at offset 0xE002:
+ 
+	db	'AUTHORS CAB93GLB93RWS93DJC93NPB(C)Copyright COMPAQ Computer Corporation 1982,83,84,85,86'
+
+Anyone care to take a stab at what `CAB93GLB93RWS93DJC93NPB` means?  I've already confirmed that
+[Google](https://www.google.com/?gws_rd=ssl#q=CAB93GLB93RWS93DJC93NPB) doesn't know.
diff --git a/modules/htmlout/lib/htmlout.js b/modules/htmlout/lib/htmlout.js
index a198c0b49..ac37059fe 100644
--- a/modules/htmlout/lib/htmlout.js
+++ b/modules/htmlout/lib/htmlout.js
@@ -175,6 +175,7 @@ var asExtsPlainText = [
     "bas",
     "hex",
     "map",
+    "nasm",
     "txt"
 ];