diff options
Diffstat (limited to 'libc/stdlib/drand48-iter.c')
| -rw-r--r-- | libc/stdlib/drand48-iter.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/libc/stdlib/drand48-iter.c b/libc/stdlib/drand48-iter.c index a69d03326..3247bafbd 100644 --- a/libc/stdlib/drand48-iter.c +++ b/libc/stdlib/drand48-iter.c @@ -27,6 +27,7 @@ struct drand48_data __libc_drand48_data; +#ifdef __UCLIBC_HAS_LONG_LONG__ int __drand48_iterate (unsigned short int xsubi[3], struct drand48_data *buffer) { @@ -55,3 +56,42 @@ __drand48_iterate (unsigned short int xsubi[3], struct drand48_data *buffer) return 0; } + +#else +int +__drand48_iterate (unsigned short int xsubi[3], struct drand48_data *buffer) +{ + uint32_t X0, X1; + uint32_t result0, result1; + + /* Initialize buffer, if not yet done. */ + if (unlikely(!buffer->__init)) + { + buffer->__a1 = 0x5; + buffer->__a0 = 0xdeece66d; + buffer->__c = 0xb; + buffer->__init = 1; + } + + /* Do the real work. We choose a data type which contains at least + 48 bits. Because we compute the modulus it does not care how + many bits really are computed. */ + + /* X = X1*base32 + X0 */ + X1 = xsubi[2]; + X0 = xsubi[0] | (uint32_t) xsubi[1] << 16; + + result0 = buffer->__a0 * X0; + result1 = (result0 > -buffer->__c ); /* Carry */ + /* If this overflows, the carry is already in result1 */ + result0 += buffer->__c; + + result1 += buffer->__a1*X0 + buffer->__a0*X1; + + xsubi[0] = result0 & 0xffff; + xsubi[1] = result0 >> 16; + xsubi[2] = result1 & 0xffff; + + return 0; +} +#endif |