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Added getTrapStatus() so that the Debugger can display trap information whenever a trap has just occurred, updated FileDump to store 'load' and 'exec' properties in MACRO-11 listing dumps (so that the individual machine files don't have to specify hard-coded 'load' and 'exec' values themselves), and added a new SerialPort parameter (upperCase) that can be used to force all received data to upper-case

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Jeff Parsons 2016-10-21 21:07:26 -07:00 • committed by Jeff Parsons
commit 5808778351
24 changed files with 269 additions and 182 deletions
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8
apps/pdp11/tapes/basic/README.md
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@ -29,13 +29,12 @@ One of the first things I noticed when debugging PDP-11 BASIC was its heavy reli
For example, `TRAP 000` is used to output the character in R2 to the terminal. Let's take a closer look at how
its TRAP handler works.
First, if you check the table of PDP-11 trap vectors, you'll see that the vector for TRAP instructions is 000034.
So let's dump the contents of the two-word vector at 000034:
Since the trap vector for TRAP instructions is fixed at address 000034, we need to dump the contents of that vector:
>> dw 034 l2
000034 000100 000000
The BASIC TRAP handler is at 000100, and here's that code:
This tells us that the BASIC TRAP handler is at 000100:
>> u 000100
000100: 011666 000002 MOV @SP,2(SP)
@ -67,7 +66,7 @@ an *even* value) into a jump table index.
The final instruction, `MOV @(SP)+,PC`, moves the address at the jump table index into PC, while also removing the TRAP
instruction from the stack, leaving only the *previous PC* on the stack.
### Comparing to SIMH
### The PDPjs Debugger vs. SIMH
How to set (and display) a breakpoint in PDPjs:
@ -81,4 +80,3 @@ How to set (and display) the same breakpoint in SIMH:
sim> break -e 016220
sim> show break
16220: E