#!/usr/bin/python
#
# This test demonstrates emulation behavior within and across
#  basic blocks.

from __future__ import print_function
import binascii
import regress
import struct

from unicorn import *
from unicorn.x86_const import *


CODE = binascii.unhexlify(b"".join([
  b"b800000000", # 1000: b8 00 00 00 00          mov    eax,0x0
  b"40",         # 1005: 40                      inc    eax
  b"40",         # 1006: 40                      inc    eax
  b"6810100000", # 1007: 68 10 10 00 00          push   0x1010
  b"c3",         # 100c: c3                      ret
  b"cc",         # 100d: cc                      int3
  b"cc",         # 100e: cc                      int3
  b"cc",         # 100f: cc                      int3
  b"b800000000", # 1010: b8 00 00 00 00          mov    eax,0x0
  b"40",         # 1015: 40                      inc    eax
  b"40",         # 1016: 40                      inc    eax 
  ]))


def showpc(mu):
    pc = mu.reg_read(UC_X86_REG_EIP)
    print("pc: 0x%x" % (pc))


class RunAcrossBBTest(regress.RegressTest):
    def test_run_across_bb(self):
        try:
            #######################################################################
            # emu SETUP
            #######################################################################


            mu = Uc(UC_ARCH_X86, UC_MODE_32)

            def hook_code(uc, address, size, user_data):
                print(">>> Tracing instruction at 0x%x, instruction size = %u" %(address, size))
            mu.hook_add(UC_HOOK_CODE, hook_code)

            # base of CODE
            mu.mem_map(0x1000, 0x1000)
            mu.mem_write(0x1000, CODE)

            # stack
            mu.mem_map(0x2000, 0x1000)

            mu.reg_write(UC_X86_REG_EIP, 0x1000)
            mu.reg_write(UC_X86_REG_ESP, 0x2800)
            self.assertEqual(0x1000, mu.reg_read(UC_X86_REG_EIP), "unexpected PC")
            self.assertEqual(0x2800, mu.reg_read(UC_X86_REG_ESP), "unexpected SP")
            showpc(mu)


            #######################################################################
            # emu_run ONE:
            #   exectue four instructions, until the last instruction in a BB
            #######################################################################


            mu.emu_start(0x1000, 0x100c)
            # should exec the following four instructions:
            # 1000: b8 00 00 00 00          mov    eax,0x0  <
            # 1005: 40                      inc    eax      <
            # 1006: 40                      inc    eax      <
            # 1007: 68 10 10 00 00          push   0x1010   <

            # should be at 0x100c, as requested
            self.assertEqual(0x100c, mu.reg_read(UC_X86_REG_EIP), "unexpected PC (2)")

            # single push, so stack diff is 0x4
            TOP_OF_STACK = 0x2800-0x4
            self.assertEqual(TOP_OF_STACK, mu.reg_read(UC_X86_REG_ESP), "unexpected SP (2)")

            # top of stack should be 0x1010
            self.assertEqual(0x1010, 
                             struct.unpack("<I", mu.mem_read(TOP_OF_STACK, 0x4))[0],
                             "unexpected stack value")
            showpc(mu)


            #######################################################################
            # emu_run TWO
            #   execute one instruction that jumps to a new BB
            #######################################################################


            mu.emu_start(0x100c, 0x1010)
            # should exec one instruction that jumps to 0x1010:
            # 100c: c3                      ret   -----------+
            # 100d: cc                      int3             |
            # 100e: cc                      int3             |
            # 100f: cc                      int3             |
            # 1010: b8 00 00 00 00          mov    eax,0x0 <-+

            # should be at 0x1010, as requested
            self.assertEqual(0x1010, mu.reg_read(UC_X86_REG_EIP), "unexpected PC (3)")

            # single pop, so stack back at base
            self.assertEqual(0x2800, mu.reg_read(UC_X86_REG_ESP), "unexpected SP (3)")
            showpc(mu)


            #######################################################################
            # emu_run THREE
            #  execute three instructions to verify things work as expected
            #######################################################################


            mu.emu_start(0x1010, 0x1016)
            # should exec the following three instructions:
            # 1010: b8 00 00 00 00          mov    eax,0x0   <
            # 1015: 40                      inc    eax       <
            # 1016: 40                      inc    eax       <
            self.assertEqual(0x1016, mu.reg_read(UC_X86_REG_EIP), "unexpected PC (4)")
            showpc(mu)

        except UcError as e:
            if e.errno == UC_ERR_FETCH_UNMAPPED:
                # during initial test dev, bad fetch at 0x1010, but the data is there,
                #   and this proves it
                print("!!! about to bail due to bad fetch... here's the data at PC:")
                print(binascii.hexlify(mu.mem_read(mu.reg_read(UC_X86_REG_EIP), 0x8)))

            self.assertFalse(True, "ERROR: %s @ 0x%x" % (e, mu.reg_read(UC_X86_REG_EIP)))


if __name__ == '__main__':
    regress.main()