From 0eee5a262467177b059bbec63fb2358fb2cc4310 Mon Sep 17 00:00:00 2001
From: n loewen <nick@nloewen.com>
Date: Tue, 29 Aug 2023 08:55:03 -0400
Subject: [PATCH] Move issues and notes back into this branch

---
 issues/issues.md | 46 ++++++++++++++++++++++++++++++++++++++++
 issues/todo.md   | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 issues/issues.md
 create mode 100644 issues/todo.md

diff --git a/issues/issues.md b/issues/issues.md
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+# Cardiograph issues
+
+## Open
+
+### #1 - Improve CLI interface
+
+I'm thinking of an interface like this...
+
+    $ ./cpu.js -mc code.bin  
+    $ ./cpu.js code.asm
+    $ ./cpu.js --debug code.asm
+
+Full list of flags I want:
+
+    -d --debug
+    -s --singlestep
+    -p --prettydisplay
+    -mc --machinecode
+
+### #2 - Startup: Execute `JMP $FF`
+
+See [2023-08-24](../notes/2023-08-24--dev-notes.md#cpu-start-up)
+
+... say that there's a 1-byte ROM at $FF.
+
+- `00-19` - display (5x5)
+- `1A   ` - pointer to display memory
+- `1B   ` - keypad: value of latest key pressed
+- `1C   ` - reserved for future use (bank switching flag)
+- `1D   ` - initial IP
+- `1D-FE` - free
+- `FF   ` - ROM (unwriteable) - pointer to initial IP
+
+- store `$1D` at `$FF`
+- make CPU execute `JMP $FF` on startup
+- make ROM unwriteable
+
+More step-by-step:
+
+  - Change memory from a Uint8Array to a regular array,
+    and make every entry { number | { type: 'ROM', value: number }}
+  - Store ROM as an object in machine.config.js
+  - Load ROM data into memory at CPU startup (`startCPU(RAM, ROM)`)
+
+
+## Closed
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diff --git a/issues/todo.md b/issues/todo.md
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+# To do — Summary
+
+This is a quick todo list.
+
+For extended commentary, see [issues](issues.md).
+
+## Open
+
+### Todo
+
+- Finish WIP on run-cli arg parsing
+- Pass CYCLE_COUNT as a cli arg
+
+- (cpu) !! Fix overflow flag
+- Add a flag for bank-switching to the ~zero-page
+- Remove run-scripts and add the ability to run `./cpu.js` and `./assembler.js` directly -- cf. [#1](issues.md#1---improve-cli-interface)
+- [fix] (cpu) Make single-stepping work with simulated keypad
+
+### Features
+
+- (cpu) allow arrow keys, too
+- [fix] (cpu) Execute `JMP $FF` on startup / Implement ROM — see [#2](issues.md#2---startup-execute-jmp-ff)
+- (assembler) Validate labels
+- (assembler) Extract debugging to its own module
+- (cpu) Consider adding a VIP-style keypad-based machine code monitor
+- (cpu) Add a mode that prints the display as text, but still animates
+- (cpu) Allow running pre-compiled machine code
+- (cpu) DRY out addition and subtraction
+- [Extended system (secret bonus operations)](../notes/2023-08-07--dev-notes.md)
+- (research) Review CHIP-8
+    - read about the spec / ISA
+    - read these, and add them to the bibliography:
+        - Steve Losh: https://stevelosh.com/blog/2016/12/chip8-input/
+        - https://tonisagrista.com/blog/2021/chip8-spec/
+
+### Documentation
+
+- Improve docs for flags register
+
+### Testing
+
+- Display (hex) numbers
+- Greater than
+- Minimal LOGO-ish interpreter for turtle graphics
+
+
+## Closed
+
+- 2023-08-26 - [fix] (logging) - 'undefined operand' situation is caused by assembling to an initial IP of $1C, which is an odd number
+- (assembler) Pass asm line thru to cpu to print when debugging
+
+
+## Abandoned
+
+- (assembler) Return pure machine code when printing to stdout (and not in debug mode)
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