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using_2032-bit_20floating_20point_20values
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using_2032-bit_20floating_20point_20values [2018/03/31 13:19] 127.0.0.1 external edit |
using_2032-bit_20floating_20point_20values [2018/04/17 19:24] (current) tbest3112 Added syntax highlighting |
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| * **FN_ConvertFromSingle** converts a number from a single precision floating point value | * **FN_ConvertFromSingle** converts a number from a single precision floating point value | ||
| \\ | \\ | ||
| + | <code bb4w> | ||
| DEF FN_ConvertToSingle(A#) | DEF FN_ConvertToSingle(A#) | ||
| LOCAL A%,P% | LOCAL A%,P% | ||
| Line 40: | Line 41: | ||
| CALL F%,A%,A# | CALL F%,A%,A# | ||
| =A# | =A# | ||
| + | </code> | ||
| \\ **Note:** **FN_ConvertToSingle** is the same routine as **FN_f4** from the supplied //D3DLIB// library, but the assembly language has been commented and the name has been changed for clarity.\\ | \\ **Note:** **FN_ConvertToSingle** is the same routine as **FN_f4** from the supplied //D3DLIB// library, but the assembly language has been commented and the name has been changed for clarity.\\ | ||
| ---- | ---- | ||
| \\ //by Richard Russell, November 2006//\\ \\ The above routines use assembly language code to perform the conversion. An alternative is to use Windows API functions as follows:\\ \\ | \\ //by Richard Russell, November 2006//\\ \\ The above routines use assembly language code to perform the conversion. An alternative is to use Windows API functions as follows:\\ \\ | ||
| + | <code bb4w> | ||
| DEF FN_ConvertToSingle(A#) | DEF FN_ConvertToSingle(A#) | ||
| LOCAL A% | LOCAL A% | ||
| Line 63: | Line 66: | ||
| SYS F%,A%,^A# | SYS F%,A%,^A# | ||
| =A# | =A# | ||
| + | </code> | ||
| If speed is critical, use this conversion function:\\ | If speed is critical, use this conversion function:\\ | ||
| + | <code bb4w> | ||
| DEF FN_ConvertToSingle(A#)=USR(f4) | DEF FN_ConvertToSingle(A#)=USR(f4) | ||
| + | </code> | ||
| where the routine **f4** has been assembled previously as follows:\\ | where the routine **f4** has been assembled previously as follows:\\ | ||
| + | <code bb4w> | ||
| .f4 | .f4 | ||
| mov ecx,[^A#+4] | mov ecx,[^A#+4] | ||
| Line 94: | Line 101: | ||
| pop eax | pop eax | ||
| ret | ret | ||
| + | </code> | ||
| Ensure there is at least a 2048-byte gap between the code and any writable data, to prevent thrashing of the instruction cache. | Ensure there is at least a 2048-byte gap between the code and any writable data, to prevent thrashing of the instruction cache. | ||
using_2032-bit_20floating_20point_20values.1522502388.txt.gz ยท Last modified: 2018/03/31 13:19 by 127.0.0.1
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