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Reverse engineering PDP-11 BASIC: Part 26
This short post describes TRAP 116 and the BASIC RUN, STOP, END and RANDOMIZE commands. For context and a list of other posts on this...
daveor
Apr 7, 2021
319 views
3 comments
Reverse engineering PDP-11 BASIC: Part 25
This post describes the BASIC FOR and NEXT loop commands. For context and a list of other posts on this topic, see the PDP-11 BASIC...
daveor
Apr 6, 2021
87 views
0 comments
Reverse engineering PDP-11 BASIC: Part 24
This post describes the BASIC READ, INPUT and RESTORE commands. For context and a list of other posts on this topic, see the PDP-11 BASIC...
daveor
Mar 27, 2021
164 views
1 comment
Reverse engineering PDP-11 BASIC: Part 23
This post describes the BASIC IF command. For context and a list of other posts on this topic, see the PDP-11 BASIC reverse engineering...
daveor
Mar 22, 2021
104 views
0 comments
Reverse engineering PDP-11 BASIC: Part 22
This post will describe the operation of TRAP 124 and the BASIC DIM and LET commands. For completeness, I'll also describe the DATA and...
daveor
Mar 21, 2021
52 views
0 comments
Reverse engineering PDP-11 BASIC: Part 21
In this post we'll look at the expression evaluation code. Expressions are used all over the place and the main entry point to parsing...
daveor
Mar 18, 2021
65 views
1 comment
Reverse engineering PDP-11 BASIC: Part 20
This post will describe the operation of a few TRAPs that are used to support the functionality that will be analysed in the next posts....
daveor
Mar 18, 2021
54 views
0 comments
Reverse engineering PDP-11 BASIC: Part 19
In this post I'll describe user-defined functions and the BASIC DEF command, starting with some TRAPs that support its operation (TRAP...
daveor
Mar 3, 2021
70 views
0 comments
Reverse engineering PDP-11 BASIC: Part 18
This post will describe the operation of the ASCII-to-floating point conversion code, TRAP 6. You will need to have read Part 14, Part...
daveor
Mar 2, 2021
62 views
0 comments
Reverse engineering PDP-11 BASIC: Part 17
This post will take a look at some more floating point manipulation TRAPs; TRAP 26 (floating point division) and TRAP 34 (floating point...
daveor
Mar 1, 2021
60 views
0 comments
Reverse engineering PDP-11 BASIC: Part 16
This post is about multiplication. There are three different multiplication TRAPs found in the PDP-11 BASIC code, with a different one...
daveor
Feb 27, 2021
88 views
0 comments
Reverse engineering PDP-11 BASIC: Part 15
This post will examine some of the floating point operations. We'll be looking at TRAP 24 (negate a floating point number), TRAP 20 (add...
daveor
Feb 24, 2021
48 views
0 comments
Reverse engineering PDP-11 BASIC: Part 14
In this post I'm going to start the analysis of the floating point number code. I will be looking at the PDP-11 BASIC representation of...
daveor
Feb 22, 2021
175 views
0 comments
Reverse engineering PDP-11 BASIC: Part 13
Update 1st March 2021: This post has been updated to reflect refined understanding of TRAP 64 arising from analysis of the floating point...
daveor
Feb 15, 2021
130 views
1 comment
Reverse engineering PDP-11 BASIC: Part 12
In this post I'll describe some of the BASIC commands that use runtime state storage, including GOSUB, GOTO and RETURN. For context and a...
daveor
Feb 10, 2021
55 views
0 comments
Reverse engineering PDP-11 BASIC: Part 11
This posts begins the analysis of the BASIC program's runtime state management. I'll start with a quick introduction to how the runtime...
daveor
Feb 9, 2021
127 views
0 comments
Reverse engineering PDP-11 BASIC: Part 10
In this post I'll be looking at how the SAVE, OLD and DELETE BASIC commands work. For context and a list of other posts on this topic,...
daveor
Feb 8, 2021
122 views
1 comment
Reverse engineering PDP-11 BASIC: Part 9
In this post I'll be looking at how the BASIC LIST command works. For context and a list of other posts on this topic, see the PDP-11...
daveor
Feb 5, 2021
71 views
0 comments
Reverse engineering PDP-11 BASIC: Part 8
In Part 6 I analysed the code that: Determined whether the user has pressed return, in which case control returns to the beginning of the...
daveor
Feb 3, 2021
82 views
0 comments
Reverse engineering PDP-11 BASIC: Part 7
The purpose of this post is to lay the groundwork required to complete the analysis of the main syntax parsing loop. There are a few...
daveor
Feb 2, 2021
91 views
0 comments
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