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Minor Debugger improvements, notes, etc, while debugging the PDP-11 BASIC

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This commit is contained in:
Jeff Parsons 2016-10-20 22:56:29 -07:00 • committed by Jeff Parsons
commit aa2a25c5ec
7 changed files with 163 additions and 94 deletions
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8
modules/pdp11/lib/ram.js
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@ -258,8 +258,8 @@ RAMPDP11.prototype.loadImage = function(aBytes, addrLoad, addrExec, addrInit)
* unless the address is odd (usually 1). DEC's "Absolute Loader" jumps to the exec address
* in former case, halts in the latter.
*
* All values are stored "little endian" (low byte first, followed by high byte), just like
* the PDP-11 does.
* All values are stored "little endian" (low byte followed by high byte), just like the
* PDP-11's memory architecture.
*
* After the data bytes, there is a single checksum byte. The 8-bit sum of all the bytes in
* the block (including the header bytes and checksum byte) should be zero.
@ -267,7 +267,9 @@ RAMPDP11.prototype.loadImage = function(aBytes, addrLoad, addrExec, addrInit)
* ANOMALIES: Tape files don't always begin with a signature word, so I allow any number of
* leading zeros before the first signature. Tape files don't always end cleanly either, so as
* soon as I see an invalid signature, I break out of the loop without signalling an error, as
* long as at least ONE block was successfully processed.
* long as at least ONE block was successfully processed. In fact, it's possible that as
* soon as a block with ZERO data bytes is encountered, processing is supposed to stop, but
* I haven't examined enough tapes (or the Absolute Loader code) to know for sure.
*/
if (addrLoad == null) {
var off = 0, fError = false;