+++ /dev/null
-#include <stdio.h>\r
-\r
-typedef unsigned int u32;\r
-\r
-u32 arm_imm_find_nonzero(u32 imm, u32 start_bit)\r
-{\r
- u32 i;\r
-\r
- for(i = start_bit; i < 32; i += 2)\r
- {\r
- if((imm >> i) & 0x03)\r
- break;\r
- }\r
-\r
- return i;\r
-}\r
-\r
-u32 arm_disect_imm_32bit(u32 imm, u32 *stores, u32 *rotations)\r
-{\r
- u32 store_count = 0;\r
- u32 left_shift = 0;\r
-\r
- // Otherwise it'll return 0 things to store because it'll never\r
- // find anything.\r
- if(imm == 0)\r
- {\r
- rotations[0] = 0;\r
- stores[0] = 0;\r
- return 1;\r
- }\r
-\r
- // Find chunks of non-zero data at 2 bit alignments.\r
- while(1)\r
- {\r
- left_shift = arm_imm_find_nonzero(imm, left_shift);\r
-\r
- if(left_shift == 32)\r
- {\r
- // We've hit the end of the useful data.\r
- return store_count;\r
- }\r
-\r
- // Hit the end, it might wrap back around to the beginning.\r
- if(left_shift >= 24)\r
- {\r
- // Make a mask for the residual bits. IE, if we have\r
- // 5 bits of data at the end we can wrap around to 3\r
- // bits of data in the beginning. Thus the first\r
- // thing, after being shifted left, has to be less\r
- // than 111b, 0x7, or (1 << 3) - 1.\r
- u32 top_bits = 32 - left_shift;\r
- u32 residual_bits = 8 - top_bits;\r
- u32 residual_mask = (1 << residual_bits) - 1;\r
-\r
- if((store_count > 1) && (left_shift > 24) &&\r
- ((stores[0] << (32 - rotations[0])) < residual_mask))\r
- {\r
- // Then we can throw out the last bit and tack it on\r
- // to the first bit.\r
- u32 initial_bits = rotations[0];\r
- stores[0] = (stores[0] << (top_bits + (32 - rotations[0]))) |\r
- ((imm >> left_shift) & 0xFF);\r
- rotations[0] = top_bits;\r
-\r
- return store_count;\r
- }\r
- else\r
- {\r
- // There's nothing to wrap over to in the beginning\r
- stores[store_count] = (imm >> left_shift) & 0xFF;\r
- rotations[store_count] = (32 - left_shift) & 0x1F;\r
- return store_count + 1;\r
- }\r
- break;\r
- }\r
-\r
- stores[store_count] = (imm >> left_shift) & 0xFF;\r
- rotations[store_count] = (32 - left_shift) & 0x1F;\r
-\r
- store_count++;\r
- left_shift += 8;\r
- }\r
-}\r
-\r
-#define ror(value, shift) \\r
- ((value) >> shift) | ((value) << (32 - shift)) \\r
-\r
-u32 arm_assemble_imm_32bit(u32 *stores, u32 *rotations, u32 store_count)\r
-{\r
- u32 n = ror(stores[0], rotations[0]);\r
- u32 i;\r
- printf("%x : %x\n", stores[0], rotations[0]);\r
-\r
- for(i = 1; i < store_count; i++)\r
- {\r
- printf("%x : %x\n", stores[i], rotations[i]);\r
- n |= ror(stores[i], rotations[i]);\r
- }\r
-\r
- return n;\r
-}\r
-\r
-\r
-int main(int argc, char *argv[])\r
-{\r
- u32 n = 0;\r
- u32 stores[4];\r
- u32 rotations[4];\r
- u32 store_count;\r
- u32 n2;\r
-\r
- if(argc != 1)\r
- {\r
- n = strtoul(argv[1], NULL, 16);\r
- store_count = arm_disect_imm_32bit(n, stores, rotations);\r
- n2 = arm_assemble_imm_32bit(stores, rotations, store_count);\r
- printf("%08x -> %08x (%d stores)\n", n, n2, store_count);\r
- return 0;\r
- }\r
-\r
- do\r
- {\r
- store_count = arm_disect_imm_32bit(n, stores, rotations);\r
- n2 = arm_assemble_imm_32bit(stores, rotations, store_count);\r
- if(n != n2)\r
- {\r
- printf("Failure: %08x -/-> %08x\n", n, n2);\r
- return -1;\r
- }\r
- n++;\r
- } while(n != 0);\r
-\r
- printf("Done!\n");\r
- return 0;\r
-}\r