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Rappel: A REPL for x86, amd64, and armv7

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Re: Rappel: A REPL for x86, amd64, and armv7

#11

Post by junke »

drudru11 wrote: post #5

This is cool. In the old days... computers came with these things built into the ROM (BIOS, Firmware, etc.). They were mostly called a 'ROM Monitor' or just the 'Monitor'. I never knew why they were called that, but I would guess that it was probably a term DEC or IBM invented. On a Sun, NeXT, or Cisco box, you could hit a magic keyboard sequence (or send an RS-232 BREAK over the console) to get to the monitor. It wa…

I remember issuing "call -151" on an Apple IIe to enter the monitor. I was too young to understand how it worked, but I was using the examples from the manual to define fast-drawing code for shapes (defined with an existing language made of combinations of down, left, right, up etc. commands) that could be called from Basic.

Re: Rappel: A REPL for x86, amd64, and armv7

#12

Post by hiteshk_msft »

drudru11 wrote: post #5

This is cool. In the old days... computers came with these things built into the ROM (BIOS, Firmware, etc.). They were mostly called a 'ROM Monitor' or just the 'Monitor'. I never knew why they were called that, but I would guess that it was probably a term DEC or IBM invented. On a Sun, NeXT, or Cisco box, you could hit a magic keyboard sequence (or send an RS-232 BREAK over the console) to get to the monitor. It wa…

This sounds similar to kernel debugging- is that what you have in mind? Windows (the OS I'm most familiar with) has a couple different styles of kernel debugging, which allows you to introspect various levels of system state:

https://msdn.microsoft.com/en-us/library/windows/hardware/ff...

https://msdn.microsoft.com/en-us/library/windows/hardware/hh...

Re: Rappel: A REPL for x86, amd64, and armv7

#16

Post by xvilka »

Same could be done using radare2 [1] tool in debug mode ("r2 -d") and using "dxa" command, to write an opcode using assembly language and execute it in place. Or even using simple C-like language (called regg [2]) to do the same.

P.S. It's always better to try radare2 from git, since it's very actively developed.

[1] http://rada.re

[2] https://github.com/radare/radare2/tree/master/libr/egg

Re: Rappel: A REPL for x86, amd64, and armv7

#17

Post by vidarh »

drudru11 wrote: post #5

This is cool. In the old days... computers came with these things built into the ROM (BIOS, Firmware, etc.). They were mostly called a 'ROM Monitor' or just the 'Monitor'. I never knew why they were called that, but I would guess that it was probably a term DEC or IBM invented. On a Sun, NeXT, or Cisco box, you could hit a magic keyboard sequence (or send an RS-232 BREAK over the console) to get to the monitor. It wa…

Monitors were also an integral feature of most "freezer" cartridges for the C64, like Action Replay and The Final Cartridge I/II/III (you could get monitors you'd load into RAM as well, but the freezer cartridges had lots of extra capabilities and of course the advantage of having the monitor in ROM). For a couple of years, until I got hold of Turbo Assembler (no relation to the Borland PC assembler), I wrote most of my assembler straight into memory using the Action Replay monitor.
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