diff options
Diffstat (limited to 'gcc/cppexp.c')
| -rw-r--r-- | gcc/cppexp.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/cppexp.c b/gcc/cppexp.c index 1153768dedd..e5f464eaa00 100644 --- a/gcc/cppexp.c +++ b/gcc/cppexp.c @@ -995,6 +995,33 @@ num_positive (num, precision) return (num.low & (cpp_num_part) 1 << (precision - 1)) == 0; } +/* Sign extend a number, with PRECISION significant bits and all + others assumed clear, to fill out a cpp_num structure. */ +cpp_num +cpp_num_sign_extend (num, precision) + cpp_num num; + size_t precision; +{ + if (!num.unsignedp) + { + if (precision > PART_PRECISION) + { + precision -= PART_PRECISION; + if (precision < PART_PRECISION + && (num.high & (cpp_num_part) 1 << (precision - 1))) + num.high |= ~(~(cpp_num_part) 0 >> (PART_PRECISION - precision)); + } + else if (num.low & (cpp_num_part) 1 << (precision - 1)) + { + if (precision < PART_PRECISION) + num.low |= ~(~(cpp_num_part) 0 >> (PART_PRECISION - precision)); + num.high = ~(cpp_num_part) 0; + } + } + + return num; +} + /* Returns the negative of NUM. */ static cpp_num num_negate (num, precision) |