diff options
Diffstat (limited to '05')
| -rw-r--r-- | 05/main.c | 2 | ||||
| -rw-r--r-- | 05/tokenize.b | 92 |
2 files changed, 51 insertions, 43 deletions
@@ -2,4 +2,4 @@ char * = "How are you"" d""o""i""ng today?\n"; hi _TEST _ING _1 -50.1e100 +5e+307 diff --git a/05/tokenize.b b/05/tokenize.b index 4868445..f85dccf 100644 --- a/05/tokenize.b +++ b/05/tokenize.b @@ -283,28 +283,9 @@ function tokenize :float_no_fraction ; construct the number integer + fraction*10^pow10 ; first, deal with the fractional part - p = powers_of_10 - p += pow10 < 4 - full_multiply_signed(fraction, *8p, &lower, &upper) - if upper == 0 goto fmultiply_no_upper - n = leftmost_1bit(upper) - n += 1 - significand = lower > n - exponent += n - n = 64 - n - significand |= upper < n - goto fmultiply_cont - :fmultiply_no_upper - significand = lower - goto fmultiply_cont - :fmultiply_cont - p += 8 - exponent += *8p + significand = fraction + float_multiply_by_power_of_10(&significand, &exponent, pow10) - putn(significand) - putc(32) - putn_signed(exponent) - putc(10) if integer == 0 goto float_no_integer ; now deal with the integer part new_exponent = leftmost_1bit(integer) @@ -324,7 +305,9 @@ function tokenize putc(32) putn_signed(exponent) putc(10) - significand += 15 ; ensure number rounds to the nearest representable float (this is what gcc does) + ; make number round to the nearest representable float roughly (this is what gcc does) + ; this fails for 5e-100 probably because of imprecision, but mostly works + significand += 15 ; reduce to 53-bit significand (top bit is removed to get 52) significand >= 5 exponent += 5 @@ -333,6 +316,9 @@ function tokenize b = 1 < n significand &= ~b data = significand + + if exponent <= -1023 goto float_zero ; this number is too small in magnitude to be represented as a double. it becomes 0 + if exponent >= 1024 goto float_infinity ; number too big to be represented as a double. exponent += 1023 ; float format data |= exponent < 52 @@ -351,23 +337,7 @@ function tokenize ; e.g. 1e100 pow10 = strtoi(&in, 10) :float_have_exponent - p = powers_of_10 - p += pow10 < 4 - full_multiply_signed(significand, *8p, &lower, &upper) - if upper == 0 goto fmultiply2_no_upper - n = leftmost_1bit(upper) - n += 1 - significand = lower > n - exponent += n - n = 64 - n - significand |= upper < n - goto fmultiply2_cont - :fmultiply2_no_upper - significand = lower - goto fmultiply2_cont - :fmultiply2_cont - p += 8 - exponent += *8p + float_multiply_by_power_of_10(&significand, &exponent, pow10) goto float_have_significand_and_exponent :float_exponent_plus ; e.g. 1e+100 @@ -381,8 +351,11 @@ function tokenize pow10 = 0 - pow10 goto float_have_exponent :float_zero - data = 0 - goto float_have_data + data = 0 + goto float_have_data + :float_infinity + data = 0x7ff0000000000000 ; double infinity + goto float_have_data :tokenize_loop_end return 0 @@ -416,7 +389,42 @@ function tokenize :str_bad_float string Bad floating-point number. byte 0 - + +function float_multiply_by_power_of_10 + argument p_significand + argument p_exponent + argument pow10 + local significand + local exponent + local p + local lower + local upper + local n + significand = *8p_significand + exponent = *8p_exponent + + p = powers_of_10 + p += pow10 < 4 + full_multiply_signed(significand, *8p, &lower, &upper) + if upper == 0 goto fmultiply2_no_upper + n = leftmost_1bit(upper) + n += 1 + significand = lower > n + exponent += n + n = 64 - n + significand |= upper < n + goto fmultiply2_cont + :fmultiply2_no_upper + significand = lower + goto fmultiply2_cont + :fmultiply2_cont + p += 8 + exponent += *8p + + *8p_significand = significand + *8p_exponent = exponent + return 0 + ; return character or escaped character from *p_in, advancing accordingly ; returns -1 on bad character function read_c_char |