Re: Efficient output for integer types

>>>>> "David" == David Fetter <david(at)fetter(dot)org> writes:

David> + /* Compute the result string. */
David> + if (value >= 100000000)
David> + {
David> + const uint32 value2 = value % 100000000;
David> +
David> + const uint32 c = value2 % 10000;
David> + const uint32 d = value2 / 10000;
David> + const uint32 c0 = (c % 100) << 1;
David> + const uint32 c1 = (c / 100) << 1;
David> + const uint32 d0 = (d % 100) << 1;
David> + const uint32 d1 = (d / 100) << 1;
David> +
David> + char *pos = a + olength - i;
David> +
David> + value /= 100000000;
David> +
David> + memcpy(pos - 2, DIGIT_TABLE + c0, 2);
David> + memcpy(pos - 4, DIGIT_TABLE + c1, 2);
David> + memcpy(pos - 6, DIGIT_TABLE + d0, 2);
David> + memcpy(pos - 8, DIGIT_TABLE + d1, 2);
David> + i += 8;
David> + }

For the 32-bit case, there's no point in doing an 8-digit divide
specially, it doesn't save any time. It's sufficient to just change

David> + if (value >= 10000)

to while(value >= 10000)

in order to process 4 digits at a time.

David> + for(int i = 0; i < minwidth - len; i++)
David> + {
David> + memcpy(str + i, DIGIT_TABLE, 1);
David> + }

Should be:
memset(str, '0', minwidth-len);

--
Andrew (irc:RhodiumToad)