[IDA] Hint on register

hint_register.py

# 
# Show a hint when the user's mouse is on a register
#
from idaapi import *
import idautils

def extract_reg(line, cx):
    linelen = len(line)
    if cx >= linelen:
        return

    walker_cx = 0
    byte_idx = 0
    last_reg_start_idx = None
    while walker_cx <= cx and byte_idx < linelen:
        cur = line[byte_idx]
        #print "byte_idx=%d, walker_cx=%d, cur=%d (%s)" % (byte_idx, walker_cx, ord(cur), "N/A" if ord(cur) < 32 or ord(cur) > 122 else cur)
        if cur == COLOR_ON:
            if ord(line[byte_idx + 1]) == COLOR_REG:
                last_reg_start_idx = byte_idx + 2
            byte_idx += 2
        elif cur == COLOR_OFF:
            if ord(line[byte_idx + 1]) == COLOR_REG:
                last_reg_start_idx = None
            byte_idx += 2
        else:
            byte_idx += 1
            walker_cx += 1

    if last_reg_start_idx:
        last_reg_end_idx = last_reg_start_idx
        while line[last_reg_end_idx] != COLOR_OFF and last_reg_end_idx < linelen:
            last_reg_end_idx += 1
        return line[last_reg_start_idx:last_reg_end_idx]

class Hooks(UI_Hooks):


    def get_custom_viewer_hint(self, view, place):

        from_mouse = True

        # get current line
        line = get_custom_viewer_curline(view, from_mouse)

        # get current X, Y in rows&columns space (as opposed to pixel space)
        _, cx, cy = get_custom_viewer_place(view, from_mouse)

        reg = extract_reg(line, cx)
        regstr = str(reg) if reg else ""
        insn = idautils.DecodeInstruction(place.toea())

        hintStr  = ""
        hintStr += "Instruction is : %s\n" % insn.get_canon_mnem()
        hintStr += "Register: %s" % regstr

        if insn:
            return (hintStr, 2)


uihook = Hooks()
uihook.hook()