110 lines
4.4 KiB
NASM
110 lines
4.4 KiB
NASM
;;#############################################################################
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;; FILE: CLAisqrt.asm
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;;
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;; DESCRIPTION: CLA inverse square root function using Newton Raphson
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;; Approximation
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;;
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;;#############################################################################
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;;!
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;;! Copyright: Copyright (C) 2023 Texas Instruments Incorporated -
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;;! All rights reserved not granted herein.
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;;! Limited License.
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;;!
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;;! Texas Instruments Incorporated grants a world-wide, royalty-free,
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;;! non-exclusive license under copyrights and patents it now or hereafter
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;;! owns or controls to make, have made, use, import, offer to sell and sell
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;;! ("Utilize") this software subject to the terms herein. With respect to the
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;;! foregoing patent license, such license is granted solely to the extent that
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;;! any such patent is necessary to Utilize the software alone. The patent
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;;! license shall not apply to any combinations which include this software,
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;;! other than combinations with devices manufactured by or for TI
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;;! ("TI Devices").
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;;! No hardware patent is licensed hereunder.
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;;!
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;;! Redistributions must preserve existing copyright notices and reproduce this
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;;! license (including the above copyright notice and the disclaimer and
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;;! (if applicable) source code license limitations below) in the documentation
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;;! and/or other materials provided with the distribution.
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;;!
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;;! Redistribution and use in binary form, without modification, are permitted
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;;! provided that the following conditions are met:
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;;!
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;;! * No reverse engineering, decompilation, or disassembly of this software is
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;;! permitted with respect to any software provided in binary form.
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;;! * Any redistribution and use are licensed by TI for use only
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;;! with TI Devices.
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;;! * Nothing shall obligate TI to provide you with source code for the
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;;! software licensed and provided to you in object code.
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;;!
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;;! If software source code is provided to you, modification and redistribution
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;;! of the source code are permitted provided that the following conditions
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;;! are met:
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;;!
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;;! * any redistribution and use of the source code, including any resulting
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;;! derivative works, are licensed by TI for use only with TI Devices.
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;;! * any redistribution and use of any object code compiled from the source
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;;! code and any resulting derivative works, are licensed by TI for use
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;;! only with TI Devices.
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;;!
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;;! Neither the name of Texas Instruments Incorporated nor the names of its
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;;! suppliers may be used to endorse or promote products derived from this
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;;! software without specific prior written permission.
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;;#############################################################################
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.cdecls C,LIST,"CLAmath.h"
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.include "CLAeabi.asm"
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;;----------------------------------------------------------------------------
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;; Description: Implement 1/(square root) using Newton-Raphson Method
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;;
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;; Equation: y = 1/(sqrt(x))
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;;
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;; Regs Used: MR0, MR1, MR2, MR3
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;;
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;; Input: x f32 value in memory
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;;
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;; Output: y f32 value in memory
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;; MR0 = y f32 result
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;;
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;; Benchmark: Cycles = 14
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;; Instructions = 14
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;;
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;; Scratchpad Usage: (Local Function Scratchpad Pointer (SP))
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;;
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;; |_______|<- MR3 (SP+0)
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;;
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;;----------------------------------------------------------------------------
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.def _CLAisqrt
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.sect "Cla1Prog:_CLAisqrt"
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.align 2
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.def __cla_CLAisqrt_sp
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__cla_CLAisqrt_sp .usect ".scratchpad:Cla1Prog:_CLAisqrt",2,0,1
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_CLAisqrt:
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.asmfunc
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.asg __cla_CLAisqrt_sp + 0, _save_MR3
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; Context Save
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MMOV32 @_save_MR3, MR3
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; MR0 = Number
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MEISQRTF32 MR1, MR0 ; MR1 = Ye = Estimate(1/sqrt(X))
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MMPYF32 MR2, MR0, #0.5 ; MR2 = X*0.5
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MMPYF32 MR3, MR1, MR1 ; MR3 = Ye*Ye
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MMPYF32 MR3, MR3, MR2 ; MR3 = Ye*Ye*X*0.5
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MSUBF32 MR3, #1.5,MR3 ; MR3 = 1.5 - Ye*Ye*X*0.5
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MMPYF32 MR1, MR1, MR3 ; MR1 = Ye = Ye*(1.5 - Ye*Ye*X*0.5)
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MMPYF32 MR3, MR1, MR2 ; MR3 = Ye*X*0.5
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MMPYF32 MR3, MR1, MR3 ; MR3 = Ye*Ye*X*0.5
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MSUBF32 MR3, #1.5,MR3 ; MR3 = 1.5 - Ye*Ye*X*0.5
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; Context Restore and Final Operations
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MRCNDD UNC
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MMPYF32 MR0, MR1, MR3 ; MR0 = Ye = Ye*(1.5 - Ye*Ye*X*0.5)
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MMOV32 MR0, MR0 ; Optional: set MSTF NF and ZF flags
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MMOV32 MR3,@_save_MR3
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.unasg _save_MR3
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.endasmfunc
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;; End of File
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