GemsExtract

# ======================================================================
# GEMS extract
# Extracts GEMS sound data from ROM with the help of
# a snapshot of the z80 while it was running
# (saved as a .ram file)
#
# Usage: gemsextract.py ROM_FILE
# ram file must have the same filename as ROM
# ======================================================================

import sys
import os.path

# ======================================================================
# -------------------------------------------------
# Settings
# -------------------------------------------------

# Guess the size of each sound data sections since there's no way
# to detect the size of each one
#
# change these values as you like.

SIZE_GUESS_PAT = 0x20000
SIZE_GUESS_ENV = 0x20000
SIZE_GUESS_SEQ = 0x20000
SIZE_GUESS_SMP = 0x80000

# ======================================================================
# -------------------------------------------------
# Init
# -------------------------------------------------

if len(sys.argv) == 1:
    print("ARGS: inputfile [pattnumloop]")
    exit()

if os.path.exists(sys.argv[1]) == False:
    print("File not found")
    exit()

MASTERNAME = sys.argv[1][:-4]
input_file = open(sys.argv[1],"rb")
input_ram  = open(MASTERNAME+".ram","rb")

out_pat = open("output/"+MASTERNAME+"_PBANK.bin","wb")
out_env = open("output/"+MASTERNAME+"_MBANK.bin","wb")
out_seq = open("output/"+MASTERNAME+"_SBANK.bin","wb")
out_smp = open("output/"+MASTERNAME+"_DBANK.bin","wb")
out_drv = open("output/"+MASTERNAME+"_Z80.bin","wb")

# ======================================================================
# -------------------------------------------------
# Start
# -------------------------------------------------

# search and extract driver
romPos=0
romSearch=True
print("Searching for driver in ROM...")
while romSearch:
    input_file.seek(romPos)
    a = ord(input_file.read(1)) << 24
    b = ord(input_file.read(1)) << 16
    c = ord(input_file.read(1)) << 8
    d = ord(input_file.read(1))
    romPos += 1
    e = a+b+c+d
    if e == 0xF3ED5631: # magic value
        input_file.seek(-4,1)   # 2 bytes next
        print("FOUND driver at:",hex(input_file.tell())+"\n")
        drvStart=input_file.tell()
        romSearch=False
# search end
romSearch=True
print("Searching for driver in ROM...")
while romSearch:
    input_file.seek(romPos)
    a = ord(input_file.read(1)) << 24
    b = ord(input_file.read(1)) << 16
    c = ord(input_file.read(1)) << 8
    d = ord(input_file.read(1))
    romPos += 1
    e = a+b+c+d
    if e == 0x77007CC9:
        drvEnd=input_file.tell()
        romSearch=False
#print(hex(drvStart),hex(drvEnd))
drvLen=drvEnd-drvStart
input_file.seek(drvStart)
for a in range(drvLen):
    a = ord(input_file.read(1)) & 0xFF
    out_drv.write(bytes([a]))

# search por pointers
ramPos=0
ramSearch=True
print("Searching for pointers in Z80RAM...")
while ramSearch:
    input_ram.seek(ramPos)
    a = ord(input_ram.read(1)) << 16
    b = ord(input_ram.read(1)) << 8
    c = ord(input_ram.read(1))
    ramPos += 1
    d = a+b+c
    if d == 0x10F9C3:   # magic value
        input_ram.seek(2,True)  # 2 bytes next
        print("FOUND pointers at:",hex(input_ram.tell()))
        ramSearch=False
a = ord(input_ram.read(1))&0xFF
b = (ord(input_ram.read(1))&0xFF) << 8
c = (ord(input_ram.read(1))&0xFF) << 16
addrPAT = a|b|c
a = ord(input_ram.read(1))&0xFF
b = (ord(input_ram.read(1))&0xFF) << 8
c = (ord(input_ram.read(1))&0xFF) << 16
addrENV = a|b|c
a = ord(input_ram.read(1))&0xFF
b = (ord(input_ram.read(1))&0xFF) << 8
c = (ord(input_ram.read(1))&0xFF) << 16
addrSEQ = a|b|c
a = ord(input_ram.read(1))&0xFF
b = (ord(input_ram.read(1))&0xFF) << 8
c = (ord(input_ram.read(1))&0xFF) << 16
addrSMP = a|b|c
print("PATCH:   ",hex(addrPAT))
print("ENVELOPE:",hex(addrENV))
print("SEQUENCE:",hex(addrSEQ))
print("SAMPLES: ",hex(addrSMP))

input_file.seek(addrPAT)
for b in range(SIZE_GUESS_PAT):
    a = ord(input_file.read(1))&0xFF
    out_pat.write(bytes([a]))
input_file.seek(addrENV)
for b in range(SIZE_GUESS_ENV):
    a = ord(input_file.read(1))&0xFF
    out_env.write(bytes([a]))
input_file.seek(addrSEQ)
for b in range(SIZE_GUESS_SEQ):
    a = ord(input_file.read(1))&0xFF
    out_seq.write(bytes([a]))
input_file.seek(addrSMP)
for b in range(SIZE_GUESS_SMP):
    a = ord(input_file.read(1))&0xFF
    out_smp.write(bytes([a]))

# ----------------------------
# End
# ----------------------------

input_file.close()
input_ram.close()
out_pat.close()
out_env.close()
out_seq.close()
out_smp.close()
out_drv.close()