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using_2016-bit_20floating_20point_20values
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using_2016-bit_20floating_20point_20values [2018/03/31 13:19] 127.0.0.1 external edit |
using_2016-bit_20floating_20point_20values [2018/04/17 19:23] (current) tbest3112 Added syntax highlighting |
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| * **FN_ConvertFromHalf** converts a number from a half-precision floating point value | * **FN_ConvertFromHalf** converts a number from a half-precision floating point value | ||
| \\ The difference between **FN_ConvertToHalf** and **FN_ConvertToHalfRounded** is that the former truncates towards zero, but is slightly faster, whereas the latter generates the half-precision number which is nearest to the supplied value, but is slightly slower. Use **FN_ConvertToHalf** if you know that the value can be converted exactly into half precision (for example it was returned from **FN_ConvertFromHalf**) or if you are not too concerned about accuracy. Use **FN_ConvertToHalfRounded** otherwise.\\ \\ | \\ The difference between **FN_ConvertToHalf** and **FN_ConvertToHalfRounded** is that the former truncates towards zero, but is slightly faster, whereas the latter generates the half-precision number which is nearest to the supplied value, but is slightly slower. Use **FN_ConvertToHalf** if you know that the value can be converted exactly into half precision (for example it was returned from **FN_ConvertFromHalf**) or if you are not too concerned about accuracy. Use **FN_ConvertToHalfRounded** otherwise.\\ \\ | ||
| + | <code bb4w> | ||
| DEF FN_ConvertFromHalf(A%) | DEF FN_ConvertFromHalf(A%) | ||
| LOCAL A# | LOCAL A# | ||
| Line 24: | Line 25: | ||
| A# /= 65536.0# : A% = !(^A#+4) | A# /= 65536.0# : A% = !(^A#+4) | ||
| = ((A% >> 16) AND &8000) + ((A% >> 10) AND &7FFF) + ((A% >> 9) AND 1) | = ((A% >> 16) AND &8000) + ((A% >> 10) AND &7FFF) + ((A% >> 9) AND 1) | ||
| + | </code> | ||
| Note that **FN_ConvertToHalf** and **FN_ConvertToHalfRounded** perform //no range checking// to ensure that the value you pass can be represented as a valid half-precision number. If this is important you can add a check as follows:\\ \\ | Note that **FN_ConvertToHalf** and **FN_ConvertToHalfRounded** perform //no range checking// to ensure that the value you pass can be represented as a valid half-precision number. If this is important you can add a check as follows:\\ \\ | ||
| + | <code bb4w> | ||
| DEF FN_ConvertToHalf(A#) | DEF FN_ConvertToHalf(A#) | ||
| LOCAL A% | LOCAL A% | ||
| Line 38: | Line 41: | ||
| A# /= 65536.0# : A% = !(^A#+4) | A# /= 65536.0# : A% = !(^A#+4) | ||
| = ((A% >> 16) AND &8000) + ((A% >> 10) AND &7FFF) + ((A% >> 9) AND 1) | = ((A% >> 16) AND &8000) + ((A% >> 10) AND &7FFF) + ((A% >> 9) AND 1) | ||
| + | </code> | ||
| In all cases the 16-bit half-precision value is passed in the least-significant 16-bits of a 32-bit integer. | In all cases the 16-bit half-precision value is passed in the least-significant 16-bits of a 32-bit integer. | ||
using_2016-bit_20floating_20point_20values.1522502388.txt.gz ยท Last modified: 2018/03/31 13:19 by 127.0.0.1
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