diff options
| author | Yuval Adam <yuv.adm@gmail.com> | 2014-03-16 14:41:11 +0200 |
|---|---|---|
| committer | Yuval Adam <yuv.adm@gmail.com> | 2014-03-16 14:41:11 +0200 |
| commit | 990090a4cc9070837d31e66b58d40f0c3d038741 (patch) | |
| tree | cf1b905082c364e9b223e0c5058566103138dae5 /utils/isqrt.c | |
| parent | 7f4da522479c0f00126219f0c23b804c3a93d7a6 (diff) | |
Add usblib and utils
Diffstat (limited to 'utils/isqrt.c')
| -rw-r--r-- | utils/isqrt.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/utils/isqrt.c b/utils/isqrt.c new file mode 100644 index 0000000..aa908f6 --- /dev/null +++ b/utils/isqrt.c @@ -0,0 +1,118 @@ +//*****************************************************************************
+//
+// isqrt.c - Integer square root.
+//
+// Copyright (c) 2005-2014 Texas Instruments Incorporated. All rights reserved.
+// Software License Agreement
+//
+// Texas Instruments (TI) is supplying this software for use solely and
+// exclusively on TI's microcontroller products. The software is owned by
+// TI and/or its suppliers, and is protected under applicable copyright
+// laws. You may not combine this software with "viral" open-source
+// software in order to form a larger program.
+//
+// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
+// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
+// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
+// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
+// DAMAGES, FOR ANY REASON WHATSOEVER.
+//
+// This is part of revision 2.1.0.12573 of the Tiva Utility Library.
+//
+//*****************************************************************************
+
+#include <stdint.h>
+#include "utils/isqrt.h"
+
+//*****************************************************************************
+//
+//! \addtogroup isqrt_api
+//! @{
+//
+//*****************************************************************************
+
+//*****************************************************************************
+//
+//! Compute the integer square root of an integer.
+//!
+//! \param ui32Value is the value whose square root is desired.
+//!
+//! This function will compute the integer square root of the given input
+//! value. Since the value returned is also an integer, it is actually better
+//! defined as the largest integer whose square is less than or equal to the
+//! input value.
+//!
+//! \return Returns the square root of the input value.
+//
+//*****************************************************************************
+uint32_t
+isqrt(uint32_t ui32Value)
+{
+ uint32_t ui32Rem, ui32Root, ui32Idx;
+
+ //
+ // Initialize the remainder and root to zero.
+ //
+ ui32Rem = 0;
+ ui32Root = 0;
+
+ //
+ // Loop over the sixteen bits in the root.
+ //
+ for(ui32Idx = 0; ui32Idx < 16; ui32Idx++)
+ {
+ //
+ // Shift the root up by a bit to make room for the new bit that is
+ // about to be computed.
+ //
+ ui32Root <<= 1;
+
+ //
+ // Get two more bits from the input into the remainder.
+ //
+ ui32Rem = ((ui32Rem << 2) + (ui32Value >> 30));
+ ui32Value <<= 2;
+
+ //
+ // Make the test root be 2n + 1.
+ //
+ ui32Root++;
+
+ //
+ // See if the root is greater than the remainder.
+ //
+ if(ui32Root <= ui32Rem)
+ {
+ //
+ // Subtract the test root from the remainder.
+ //
+ ui32Rem -= ui32Root;
+
+ //
+ // Increment the root, setting the second LSB.
+ //
+ ui32Root++;
+ }
+ else
+ {
+ //
+ // The root is greater than the remainder, so the new bit of the
+ // root is actually zero.
+ //
+ ui32Root--;
+ }
+ }
+
+ //
+ // Return the computed root.
+ //
+ return(ui32Root >> 1);
+}
+
+//*****************************************************************************
+//
+// Close the Doxygen group.
+//! @}
+//
+//*****************************************************************************
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