SourceGen Disassembly Listing Notes

SourceGen allows you to customize the on-screen listing to your personal tastes, configuring mnemonic capitalization, pseudo-opcode names, text delimiters, cycle count annotations, and expresson syntax. The HTML output reflects those choices. Most of the listings here use the default settings, although I generally use Merlin-style labels (':' for locals, ']' for variables).

To aid perusal, all references to global labels are links, but I found it visually distracting so I tweaked the page style to make them look like plain text.

One potentially confusing output option is expression style. LDA #>FOO+4*3 is evaluated in completely different ways by different assemblers. SourceGen's default presentation (called "common") assumes C language operators and precedence. It's useful to consider an example.

The Applesoft BASIC disassembly is based on a much older disassembly that was developed in S-C Assembler format. The original has code like this for setting the high and low bytes of a pointer:

D592- A9 D0    1650        LDA #TOKEN.NAME.TABLE-$100
D594- 85 9D    1660        STA FAC      MAKE PNTR FOR SEARCH
D596- A9 CF    1670        LDA /TOKEN.NAME.TABLE-$100
D598- 85 9E    1680        STA FAC+1

Where TOKEN.NAME.TABLE symbol is a label at address $D0D0. The order of operations imposed by the assembler matters. SourceGen can generate three different things, depending on what it's generating code for:

Merlin 32 performs the subtraction before shifting and modding, so we need to subtract $100 from the high part. (The low part is still $D0 after the subtraction, so no math needed.)
```
    lda     #<TOKEN_NAME_TABLE
    lda     #>TOKEN_NAME_TABLE-256
```
For cc65, the subtraction happens after byte selection, so we can just subtract 1.
```
    lda     #<TOKEN_NAME_TABLE
    lda     #>TOKEN_NAME_TABLE-1
```
For 64tass/ACME ("common") the subtraction happens first, but we can use parenthesis to override the order.
```
    lda     #<TOKEN_NAME_TABLE
    lda     #(>TOKEN_NAME_TABLE)-1
```

This is a fairly simple example; things get messier when 16-bit code is involved. If you find the "common" style to be too different from what you're used to, remember that you can load the project into SourceGen and re-export it with your preferred options.