ALttP Symbol File Format

Documentation for importing disassembly symbol files into YAZE.

Source: ~/Code/alttp-gigaleak/DISASM/jpdasm/symbols_*.asm

Available Symbol Files

File	Contents	Address Range
symbols_wram.asm	Work RAM labels	$7E0000-$7FFFFF
symbols_sram.asm	Save RAM labels	$700000-$70FFFF
symbols_apu.asm	Audio processor	APU addresses
registers.asm	Hardware registers	$2100-$21FF, $4200-$43FF

File Format

Simple assembly-style symbol definitions:

; Comment lines start with semicolon
SYMBOL_NAME     = $AABBCC    ; Optional inline comment
 
; Multi-line comments for documentation
; LENGTH: 0x10
BLOCK_START     = $7E0000

Symbol Naming Conventions

Suffixes

Suffix	Meaning
L	Low byte of 16-bit value
H	High byte of 16-bit value
U	Unused high byte
Q	Queue (for NMI updates)

Prefixes

Prefix	Category
LINK_	Player state
SPR_	Sprite/enemy
NMI_	NMI handler
OAM_	OAM buffer
UNUSED_	Free RAM

Bitfield Documentation

;   a - found to the north west
;   b - found to the north east
;   c - found to the south west
;   d - found to the south east
; Bitfield: abcd....
TILE_DIRECTION  = $7E000A

Key Symbols (Quick Reference)

Game State ($7E0010-$7E001F)

MODE            = $7E0010   ; Main game mode
SUBMODE         = $7E0011   ; Sub-mode within mode
LAG             = $7E0012   ; NMI sync flag
INIDISPQ        = $7E0013   ; Display brightness queue
NMISTRIPES      = $7E0014   ; Tilemap update flag
NMICGRAM        = $7E0015   ; Palette update flag

Player Position (typical)

LINK_X_LO       = $7E0022   ; Link X position (low)
LINK_X_HI       = $7E0023   ; Link X position (high)
LINK_Y_LO       = $7E0020   ; Link Y position (low)
LINK_Y_HI       = $7E0021   ; Link Y position (high)
LINK_LAYER      = $7E00EE   ; Current layer (0=BG1, 1=BG2)

Room/Dungeon

ROOM_ID         = $7E00A0   ; Current room number
DUNGEON_ID      = $7E040C   ; Current dungeon

C++ Parser

#include <string>
#include <unordered_map>
#include <fstream>
#include <sstream>
#include <regex>
 
struct Symbol {
    std::string name;
    uint32_t address;
    std::string comment;
};
 
std::unordered_map<uint32_t, Symbol> parse_symbols(const std::string& path) {
    std::unordered_map<uint32_t, Symbol> symbols;
    std::ifstream file(path);
    std::string line;
 
    // Pattern: NAME = $ADDRESS  ; comment
    std::regex pattern(R"(^(\w+)\s*=\s*\$([0-9A-Fa-f]+)\s*(?:;\s*(.*))?$)");
 
    while (std::getline(file, line)) {
        // Skip pure comment lines
        if (line.empty() || line[0] == ';') continue;
 
        std::smatch match;
        if (std::regex_search(line, match, pattern)) {
            Symbol sym;
            sym.name = match[1].str();
            sym.address = std::stoul(match[2].str(), nullptr, 16);
            sym.comment = match[3].str();
 
            symbols[sym.address] = sym;
        }
    }
 
    return symbols;
}
 
// Get symbol name for address (returns empty if not found)
std::string lookup_symbol(const std::unordered_map<uint32_t, Symbol>& syms,
                          uint32_t addr) {
    auto it = syms.find(addr);
    return (it != syms.end()) ? it->second.name : "";
}

Integration Ideas

Hex Editor Enhancement

// Display symbol alongside address
void draw_hex_line(uint32_t addr, const uint8_t* data) {
    std::string sym = lookup_symbol(symbols, addr);
    if (!sym.empty()) {
        printf("%06X  %-20s  ", addr, sym.c_str());
    } else {
        printf("%06X  %-20s  ", addr, "");
    }
    // ... draw hex bytes
}

Disassembly View

// Replace addresses with symbols in ASM output
std::string format_operand(uint32_t addr) {
    std::string sym = lookup_symbol(symbols, addr);
    if (!sym.empty()) {
        return sym;
    }
    return "$" + to_hex(addr);
}

Memory Watcher

struct Watch {
    std::string label;
    uint32_t address;
    uint8_t size;  // 1, 2, or 3 bytes
};
 
// Auto-populate watches from symbol file
std::vector<Watch> create_watches_from_symbols() {
    std::vector<Watch> watches;
 
    // Key game state
    watches.push_back({"Mode", 0x7E0010, 1});
    watches.push_back({"Submode", 0x7E0011, 1});
    watches.push_back({"Link X", 0x7E0022, 2});
    watches.push_back({"Link Y", 0x7E0020, 2});
    watches.push_back({"Room", 0x7E00A0, 2});
 
    return watches;
}

Free RAM Discovery

Symbol files mark unused RAM:

; FREE RAM: 0x20
UNUSED_7E0500   = $7E0500
UNUSED_7E0501   = $7E0501
; ...
 
; BIG FREE RAM
UNUSED_7E1000   = $7E1000  ; Large block available

Parse for FREE RAM comments to find available space for ROM hacks.

File Locations

~/Code/alttp-gigaleak/DISASM/jpdasm/
├── symbols_wram.asm    # Work RAM ($7E)
├── symbols_sram.asm    # Save RAM ($70)
├── symbols_apu.asm     # Audio
├── registers.asm       # Hardware registers
└── registers_spc.asm   # SPC700 registers