diff options
Diffstat (limited to 'libiberty/floatformat.c')
| -rw-r--r-- | libiberty/floatformat.c | 109 |
1 files changed, 49 insertions, 60 deletions
diff --git a/libiberty/floatformat.c b/libiberty/floatformat.c index 0bbb8ed..c5abbb1 100644 --- a/libiberty/floatformat.c +++ b/libiberty/floatformat.c @@ -249,53 +249,51 @@ const struct floatformat floatformat_ia64_quad_little = floatformat_always_valid }; + +#ifndef min +#define min(a, b) ((a) < (b) ? (a) : (b)) +#endif + /* Extract a field which starts at START and is LEN bits long. DATA and TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ static unsigned long get_field (const unsigned char *data, enum floatformat_byteorders order, unsigned int total_len, unsigned int start, unsigned int len) { - unsigned long result; + unsigned long result = 0; unsigned int cur_byte; - int cur_bitshift; + int lo_bit, hi_bit, cur_bitshift = 0; + int nextbyte = (order == floatformat_little) ? 1 : -1; + + /* Start is in big-endian bit order! Fix that first. */ + start = total_len - (start + len); /* Start at the least significant part of the field. */ - cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; if (order == floatformat_little) - cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1; - cur_bitshift = - ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; - result = *(data + cur_byte) >> (-cur_bitshift); - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; + cur_byte = start / FLOATFORMAT_CHAR_BIT; else - --cur_byte; + cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; - /* Move towards the most significant part of the field. */ - while ((unsigned int) cur_bitshift < len) + lo_bit = start % FLOATFORMAT_CHAR_BIT; + hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); + + do { - if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) - /* This is the last byte; zero out the bits which are not part of - this field. */ - result |= - (*(data + cur_byte) & ((1 << (len - cur_bitshift)) - 1)) - << cur_bitshift; - else - result |= *(data + cur_byte) << cur_bitshift; - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; - else - --cur_byte; + unsigned int shifted = *(data + cur_byte) >> lo_bit; + unsigned int bits = hi_bit - lo_bit; + unsigned int mask = (1 << bits) - 1; + result |= (shifted & mask) << cur_bitshift; + len -= bits; + cur_bitshift += bits; + cur_byte += nextbyte; + lo_bit = 0; + hi_bit = min (len, FLOATFORMAT_CHAR_BIT); } + while (len != 0); + return result; } -#ifndef min -#define min(a, b) ((a) < (b) ? (a) : (b)) -#endif - /* Convert from FMT to a double. FROM is the address of the extended float. Store the double in *TO. */ @@ -428,43 +426,34 @@ put_field (unsigned char *data, enum floatformat_byteorders order, unsigned long stuff_to_put) { unsigned int cur_byte; - int cur_bitshift; + int lo_bit, hi_bit; + int nextbyte = (order == floatformat_little) ? 1 : -1; + + /* Start is in big-endian bit order! Fix that first. */ + start = total_len - (start + len); /* Start at the least significant part of the field. */ - cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1; - cur_bitshift = - ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; - *(data + cur_byte) &= - ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) << (-cur_bitshift)); - *(data + cur_byte) |= - (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift); - cur_bitshift += FLOATFORMAT_CHAR_BIT; if (order == floatformat_little) - ++cur_byte; + cur_byte = start / FLOATFORMAT_CHAR_BIT; else - --cur_byte; + cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; - /* Move towards the most significant part of the field. */ - while ((unsigned int) cur_bitshift < len) + lo_bit = start % FLOATFORMAT_CHAR_BIT; + hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); + + do { - if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) - { - /* This is the last byte. */ - *(data + cur_byte) &= - ~((1 << (len - cur_bitshift)) - 1); - *(data + cur_byte) |= (stuff_to_put >> cur_bitshift); - } - else - *(data + cur_byte) = ((stuff_to_put >> cur_bitshift) - & ((1 << FLOATFORMAT_CHAR_BIT) - 1)); - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; - else - --cur_byte; + unsigned char *byte_ptr = data + cur_byte; + unsigned int bits = hi_bit - lo_bit; + unsigned int mask = ((1 << bits) - 1) << lo_bit; + *byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask); + stuff_to_put >>= bits; + len -= bits; + cur_byte += nextbyte; + lo_bit = 0; + hi_bit = min (len, FLOATFORMAT_CHAR_BIT); } + while (len != 0); } /* The converse: convert the double *FROM to an extended float |