#!/usr/bin/env python3
"""sbl_adr.py — поиск ADR (ADD/SUB pc) ссылок на интересные строки SBL1.
Использование: ./tools/sbl_adr.py fw/sbl/img0.elf
"""
import struct
import sys

d = open(sys.argv[1], "rb").read()
STRINGS = [b"SBL1, Start", b"SBL1, End", b"SBL1, Delta",
           b"Sahara: Hello pkt sent", b"bl_power_on", b"sbl1_main"]
svas = {}
for s in STRINGS:
    i = d.find(s)
    if i < 0:
        continue
    # find which segment contains it
    phoff = struct.unpack("<I", d[28:32])[0]
    phnum = struct.unpack("<H", d[44:46])[0]
    for k in range(phnum):
        p = d[phoff + k * 32:phoff + (k + 1) * 32]
        t, off, v, pa, fsz, msz, fl, al = struct.unpack("<IIIIIIII", p)
        if t == 1 and off <= i < off + fsz:
            svas[s] = v + (i - off)
for s, va in svas.items():
    print(s.decode(), "VA:", hex(va))

phoff = struct.unpack("<I", d[28:32])[0]
phnum = struct.unpack("<H", d[44:46])[0]
segs = []
for k in range(phnum):
    p = d[phoff + k * 32:phoff + (k + 1) * 32]
    t, off, v, pa, fsz, msz, fl, al = struct.unpack("<IIIIIIII", p)
    if t == 1 and fsz and (fl & 1 or True):
        segs.append((off, v, fsz))
for s, va in svas.items():
    print("--- refs to", s.decode(), hex(va))
    n = 0
    for off, v, sz in segs:
        code = d[off:off + sz]
        for j in range(0, len(code) - 4, 4):
            x = struct.unpack("<I", code[j:j + 4])[0]
            # ADD Rd,pc,#imm12 rotated; SUB Rd,pc,#imm
            if (x & 0x0FFF0000) in (0x028F0000, 0x024F0000):
                imm = x & 0xFFF
                rot = (x & 0xF00) >> 7
                imm = ((imm >> rot) | (imm << (32 - rot))) & 0xFFFFFFFF if rot else imm
                tgt = (v + j + 8 + (imm if (x & 0x400000) else -imm)) & 0xFFFFFFFF
                if abs(tgt - va) < 0x100:
                    print("  ", hex(v + j), "->", hex(tgt))
                    n += 1
                    if n > 6:
                        break