z80count 0.8.2
A tool to annotate Z80 assembler with cycle counts.
License: MIT

# z80count

This is a simple tool that parses Z80 assembler using regular expressions (I know!)
and adds comments to the code with the cycles used by the instruction.

It needs testing and probably a proper Z80 parser, but it works for me and the
Z80 assembler syntax I use.

<img src="https://git.usebox.net/z80count/plain/etc/demo-vim.gif" alt="demo" style="width:800px;">

## Install

`z80count` requires Python 3.

To install for production you can use `pip`:

    pip3 install --user z80count

Or you can download the package from [z80count's refs tab](https://git.usebox.net/z80count/refs/), unpack and run:

    python3 setup.py install

To install for development run:

    git clone https://git.usebox.net/z80count
    cd z80count
    pip3 install -e ".[dev]"

## Usage

You can use it with:

    z80count  < file.asm > file_c.asm

Or inside `vim` you can:

    :% !z80count -s

With `-s` the tool adds a subtotal.

By default `z80count` will try to update comments replacing existing annotations.

Comments added by `z80count` are aligned to the column given in the `-c`
(`--column`) option (50 by default). By default the comments are aligned using
spaces, if you prefer tabs instead use the `-t` option. In order to compute the
padding `z80count` assumes that a `TAB` equals 8 spaces. Use the
option `-T` to override this.

Example:
```asm
	push hl
	pop bc
	ld hl, $5800

	ld e, 7
.fade_out_all_loop0
	push hl
	push bc

	halt
.fade_out_all_loop1
	ld a, (hl)
	and 7
	jr z, no_fade_all_ink
	dec a
.no_fade_all_ink

	ld d, a

	ld a, (hl)
	and $38
	jr z, no_fade_all_paper
	sub 8
.no_fade_all_paper

	or d
	ld d, a

	ld a, (hl)
	and $c0
	or d

	ld (hl), a
	inc hl

	dec bc
	ld a, b
	or c
	jr nz, fade_out_all_loop1

	pop bc
	pop hl
	dec e
	jr nz, fade_out_all_loop0
```

Processed with `z80count.py -s` results in:
```asm
        push hl                         ; [11 .. 11]
        pop bc                          ; [10 .. 21]
        ld hl, $5800                    ; [10 .. 31]

        ld e, 7                         ; [7 .. 38]
.fade_out_all_loop0
        push hl                         ; [11 .. 49]
        push bc                         ; [11 .. 60]

        halt                            ; [4 .. 64]
.fade_out_all_loop1
        ld a, (hl)                      ; [7 .. 71]
        and 7                           ; [7 .. 78]
        jr z, no_fade_all_ink           ; [12/7 .. 90/85]
        dec a                           ; [4 .. 89]
.no_fade_all_ink

        ld d, a                         ; [4 .. 93]

        ld a, (hl)                      ; [7 .. 100]
        and $38                         ; [7 .. 107]
        jr z, no_fade_all_paper         ; [12/7 .. 119/114]
        sub 8                           ; [7 .. 121]
.no_fade_all_paper

        or d                            ; [4 .. 125]
        ld d, a                         ; [4 .. 129]

        ld a, (hl)                      ; [7 .. 136]
        and $c0                         ; [7 .. 143]
        or d                            ; [4 .. 147]

        ld (hl), a                      ; [7 .. 154]
        inc hl                          ; [6 .. 160]

        dec bc                          ; [6 .. 166]
        ld a, b                         ; [4 .. 170]
        or c                            ; [4 .. 174]
        jr nz, fade_out_all_loop1       ; [12/7 .. 186/181]

        pop bc                          ; [10 .. 191]
        pop hl                          ; [10 .. 201]
        dec e                           ; [4 .. 205]
        jr nz, fade_out_all_loop0       ; [12/7 .. 217/212]
```

Comments show subtotals, and there are two types:
 - `[A .. T0]`
 - `[B/A .. T1/T0]`

Where A, B, T0 and T1 are:
 - A is the number of cycles of current instruction. In case of a conditional
   instruction, this is the value when the condition is not met.
 - B is the number of cycles of current instruction when the condition is met.
 - T0 is the subtotal when the conditional is not met.
 - T1 is the subtotal when the conditional is met.

## Config file

`z80count` will look for a config file in the following places, in order:

- the file given in the environment variable `Z80COUNT_RC`.

- a file `z80countrc` in the directory given in the environment variable
  `XDG_DEFAULT_HOME` or, if this variable is undefined or empty, in
  the directory `~/.config`.

- a file `.z80countrc` in the home directory.

Example:

```
[z80count]
# Column to align newly added comments
# column = 50

# Enable debug (show the matched case)
# debug = no

# Include subtotals
# subtotals = no

# Number of spaces for each tab
# tab width = 8

# Keep previous cycle annotations in the comment
# keep cycles = no

# Use tabs to align newly added comments instead of spaces
# use tabs = yes
```

## Editor support

- [z80count-el](https://github.com/patxoca/z80count-el), emacs

## Troubleshooting

Here be dragons!

Use `-d` flag if you think one instruction is not correctly parsed.

Feel free to open a PR if you find a bug!

## Authors

 - Juan J. Martinez <jjm@usebox.net>
 - Alexis Roda https://github.com/patxoca