BBC BASIC Programmers' Reference

User Tools

Site Tools

Trace:
using_2032-bit_20floating_20point_20values

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Next revision		Previous revision
using_2032-bit_20floating_20point_20values [2018/03/31 13:19] – external edit 127.0.0.1using_2032-bit_20floating_20point_20values [2024/01/05 00:21] (current) – external edit 127.0.0.1
Line 6: Line 6:
   * **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 · Last modified: 2024/01/05 00:16 (external edit)