Z80 Coding Style and Conventions

• Whitespace
  • Tabs, not spaces
  • Instructions indented 8 tabstops
  • Space between oprands e.g. ld a, b
• Naming conventions
  • Upper case assembler directives e.g. EQU, ORG, IF, ENDIF
  • Upper case constants e.g. MAGENTA EQU %011
  • Lower case operators (opcode mnemonics) and registers e.g. push hl
  • Function names UpperCamelCase and end with colon e.g. DrawScore:
    • Local helper functions can be lowerCamelCase to make it clear they are not part of the "public" API
  • Function names starting with NB are intended as public NextBASIC API entry points
  • Local labels start with .
  • Data labels (variable names) lowerCamelCase e.g. playerScore: DW 0
    • Addresses that contain addresses (i.e. pointers) should start with a 'p' e.g. pActivePlayer DW $0000
  • Struct names UpperCamelCase e.g. STRUCT InvaderBullet
• Numbers
  • Use $ for hex literals e.g. ld hl,$4000
  • Addresses generally referenced as hex
• Comments
  • Only use semi-colon
  • Full line/standalone comments start with ;; at same indentation as opcodes
  • Capital register names in comments
  • No vertical space between comment above function and the function. Use single ; on last line if required (for VS Code intellisense)
  • Function comments should mark all input with =, output with <- and modified registers

    ;
    ; DE = address of addhend
    ; B <- sum
    ; Modifies: AF, BC, DE, HL
    ; Zero Flag <- reset if changed player, set if did not change player
    ;
    Sum:
    ...

Thanks and attribution

• Coding style structure adapted from @howprice's z80n invaders