1207753Smm/////////////////////////////////////////////////////////////////////////////// 2207753Smm// 3207753Smm/// \file armthumb.c 4207753Smm/// \brief Filter for ARM-Thumb binaries 5207753Smm/// 6207753Smm// Authors: Igor Pavlov 7207753Smm// Lasse Collin 8207753Smm// 9207753Smm// This file has been put into the public domain. 10207753Smm// You can do whatever you want with this file. 11207753Smm// 12207753Smm/////////////////////////////////////////////////////////////////////////////// 13207753Smm 14207753Smm#include "simple_private.h" 15207753Smm 16207753Smm 17207753Smmstatic size_t 18312518Sdelphijarmthumb_code(void *simple lzma_attribute((__unused__)), 19207753Smm uint32_t now_pos, bool is_encoder, 20207753Smm uint8_t *buffer, size_t size) 21207753Smm{ 22207753Smm size_t i; 23207753Smm for (i = 0; i + 4 <= size; i += 2) { 24207753Smm if ((buffer[i + 1] & 0xF8) == 0xF0 25207753Smm && (buffer[i + 3] & 0xF8) == 0xF8) { 26207753Smm uint32_t src = ((buffer[i + 1] & 0x7) << 19) 27207753Smm | (buffer[i + 0] << 11) 28207753Smm | ((buffer[i + 3] & 0x7) << 8) 29207753Smm | (buffer[i + 2]); 30207753Smm 31207753Smm src <<= 1; 32207753Smm 33207753Smm uint32_t dest; 34207753Smm if (is_encoder) 35207753Smm dest = now_pos + (uint32_t)(i) + 4 + src; 36207753Smm else 37207753Smm dest = src - (now_pos + (uint32_t)(i) + 4); 38207753Smm 39207753Smm dest >>= 1; 40207753Smm buffer[i + 1] = 0xF0 | ((dest >> 19) & 0x7); 41207753Smm buffer[i + 0] = (dest >> 11); 42207753Smm buffer[i + 3] = 0xF8 | ((dest >> 8) & 0x7); 43207753Smm buffer[i + 2] = (dest); 44207753Smm i += 2; 45207753Smm } 46207753Smm } 47207753Smm 48207753Smm return i; 49207753Smm} 50207753Smm 51207753Smm 52207753Smmstatic lzma_ret 53292588Sdelphijarmthumb_coder_init(lzma_next_coder *next, const lzma_allocator *allocator, 54207753Smm const lzma_filter_info *filters, bool is_encoder) 55207753Smm{ 56207753Smm return lzma_simple_coder_init(next, allocator, filters, 57207753Smm &armthumb_code, 0, 4, 2, is_encoder); 58207753Smm} 59207753Smm 60207753Smm 61207753Smmextern lzma_ret 62207753Smmlzma_simple_armthumb_encoder_init(lzma_next_coder *next, 63292588Sdelphij const lzma_allocator *allocator, 64292588Sdelphij const lzma_filter_info *filters) 65207753Smm{ 66207753Smm return armthumb_coder_init(next, allocator, filters, true); 67207753Smm} 68207753Smm 69207753Smm 70207753Smmextern lzma_ret 71207753Smmlzma_simple_armthumb_decoder_init(lzma_next_coder *next, 72292588Sdelphij const lzma_allocator *allocator, 73292588Sdelphij const lzma_filter_info *filters) 74207753Smm{ 75207753Smm return armthumb_coder_init(next, allocator, filters, false); 76207753Smm} 77