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- @********************************************************************************************************
- @ uC/CPU
- @ CPU CONFIGURATION & PORT LAYER
- @
- @ (c) Copyright 2004-2013; Micrium, Inc.; Weston, FL
- @
- @ All rights reserved. Protected by international copyright laws.
- @
- @ uC/CPU is provided in source form to registered licensees ONLY. It is
- @ illegal to distribute this source code to any third party unless you receive
- @ written permission by an authorized Micrium representative. Knowledge of
- @ the source code may NOT be used to develop a similar product.
- @
- @ Please help us continue to provide the Embedded community with the finest
- @ software available. Your honesty is greatly appreciated.
- @
- @ You can find our product's user manual, API reference, release notes and
- @ more information at https://doc.micrium.com.
- @ You can contact us at www.micrium.com.
- @********************************************************************************************************
-
- @********************************************************************************************************
- @
- @ CPU PORT FILE
- @
- @ ARM-Cortex-M4
- @ GNU C Compiler
- @
- @ Filename : cpu_a.asm
- @ Version : V1.30.01.00
- @ Programmer(s) : JJL
- @********************************************************************************************************
-
-
- @********************************************************************************************************
- @ PUBLIC FUNCTIONS
- @********************************************************************************************************
-
- .global CPU_IntDis
- .global CPU_IntEn
-
- .global CPU_SR_Save
- .global CPU_SR_Restore
-
- .global CPU_WaitForInt
- .global CPU_WaitForExcept
-
-
- .global CPU_CntLeadZeros
- .global CPU_CntTrailZeros
- .global CPU_RevBits
-
-
- @********************************************************************************************************
- @ CODE GENERATION DIRECTIVES
- @********************************************************************************************************
-
- .text
- .align 2
- .syntax unified
-
-
- @********************************************************************************************************
- @ DISABLE and ENABLE INTERRUPTS
- @
- @ Description: Disable/Enable interrupts.
- @
- @ Prototypes : void CPU_IntDis(void);
- @ void CPU_IntEn (void);
- @********************************************************************************************************
-
- .thumb_func
- CPU_IntDis:
- CPSID I
- BX LR
-
- .thumb_func
- CPU_IntEn:
- CPSIE I
- BX LR
-
-
- @********************************************************************************************************
- @ CRITICAL SECTION FUNCTIONS
- @
- @ Description : Disable/Enable interrupts by preserving the state of interrupts. Generally speaking, the
- @ state of the interrupt disable flag is stored in the local variable 'cpu_sr' & interrupts
- @ are then disabled ('cpu_sr' is allocated in all functions that need to disable interrupts).
- @ The previous interrupt state is restored by copying 'cpu_sr' into the CPU's status register.
- @
- @ Prototypes : CPU_SR CPU_SR_Save (void);
- @ void CPU_SR_Restore(CPU_SR cpu_sr);
- @
- @ Note(s) : (1) These functions are used in general like this :
- @
- @ void Task (void *p_arg)
- @ {
- @ CPU_SR_ALLOC(); /* Allocate storage for CPU status register */
- @ :
- @ :
- @ CPU_CRITICAL_ENTER(); /* cpu_sr = CPU_SR_Save(); */
- @ :
- @ :
- @ CPU_CRITICAL_EXIT(); /* CPU_SR_Restore(cpu_sr); */
- @ :
- @ }
- @********************************************************************************************************
-
- .thumb_func
- CPU_SR_Save:
- MRS R0, PRIMASK @ Set prio int mask to mask all (except faults)
- CPSID I
- BX LR
-
- .thumb_func
- CPU_SR_Restore: @ See Note #2.
- MSR PRIMASK, R0
- BX LR
-
-
- @********************************************************************************************************
- @ WAIT FOR INTERRUPT
- @
- @ Description : Enters sleep state, which will be exited when an interrupt is received.
- @
- @ Prototypes : void CPU_WaitForInt (void)
- @
- @ Argument(s) : none.
- @********************************************************************************************************
-
- .thumb_func
- CPU_WaitForInt:
- WFI @ Wait for interrupt
- BX LR
-
-
- @********************************************************************************************************
- @ WAIT FOR EXCEPTION
- @
- @ Description : Enters sleep state, which will be exited when an exception is received.
- @
- @ Prototypes : void CPU_WaitForExcept (void)
- @
- @ Argument(s) : none.
- @********************************************************************************************************
-
- .thumb_func
- CPU_WaitForExcept:
- WFE @ Wait for exception
- BX LR
-
-
- @********************************************************************************************************
- @ CPU_CntLeadZeros()
- @ COUNT LEADING ZEROS
- @
- @ Description : Counts the number of contiguous, most-significant, leading zero bits before the
- @ first binary one bit in a data value.
- @
- @ Prototype : CPU_DATA CPU_CntLeadZeros(CPU_DATA val);
- @
- @ Argument(s) : val Data value to count leading zero bits.
- @
- @ Return(s) : Number of contiguous, most-significant, leading zero bits in 'val'.
- @
- @ Caller(s) : Application.
- @
- @ This function is an INTERNAL CPU module function but MAY be called by application
- @ function(s).
- @
- @ Note(s) : (1) (a) Supports 32-bit data value size as configured by 'CPU_DATA' (see 'cpu.h
- @ CPU WORD CONFIGURATION Note #1').
- @
- @ (b) For 32-bit values :
- @
- @ b31 b30 b29 ... b04 b03 b02 b01 b00 # Leading Zeros
- @ --- --- --- --- --- --- --- --- ---------------
- @ 1 x x x x x x x 0
- @ 0 1 x x x x x x 1
- @ 0 0 1 x x x x x 2
- @ : : : : : : : : :
- @ : : : : : : : : :
- @ 0 0 0 1 x x x x 27
- @ 0 0 0 0 1 x x x 28
- @ 0 0 0 0 0 1 x x 29
- @ 0 0 0 0 0 0 1 x 30
- @ 0 0 0 0 0 0 0 1 31
- @ 0 0 0 0 0 0 0 0 32
- @
- @
- @ (2) MUST be defined in 'cpu_a.asm' (or 'cpu_c.c') if CPU_CFG_LEAD_ZEROS_ASM_PRESENT is
- @ #define'd in 'cpu_cfg.h' or 'cpu.h'.
- @********************************************************************************************************
-
- .thumb_func
- CPU_CntLeadZeros:
- CLZ R0, R0 @ Count leading zeros
- BX LR
-
-
- @********************************************************************************************************
- @ CPU_CntTrailZeros()
- @ COUNT TRAILING ZEROS
- @
- @ Description : Counts the number of contiguous, least-significant, trailing zero bits before the
- @ first binary one bit in a data value.
- @
- @ Prototype : CPU_DATA CPU_CntTrailZeros(CPU_DATA val);
- @
- @ Argument(s) : val Data value to count trailing zero bits.
- @
- @ Return(s) : Number of contiguous, least-significant, trailing zero bits in 'val'.
- @
- @ Caller(s) : Application.
- @
- @ This function is an INTERNAL CPU module function but MAY be called by application
- @ function(s).
- @
- @ Note(s) : (1) (a) Supports 32-bit data value size as configured by 'CPU_DATA' (see 'cpu.h
- @ CPU WORD CONFIGURATION Note #1').
- @
- @ (b) For 32-bit values :
- @
- @ b31 b30 b29 b28 b27 ... b02 b01 b00 # Trailing Zeros
- @ --- --- --- --- --- --- --- --- ----------------
- @ x x x x x x x 1 0
- @ x x x x x x 1 0 1
- @ x x x x x 1 0 0 2
- @ : : : : : : : : :
- @ : : : : : : : : :
- @ x x x x 1 0 0 0 27
- @ x x x 1 0 0 0 0 28
- @ x x 1 0 0 0 0 0 29
- @ x 1 0 0 0 0 0 0 30
- @ 1 0 0 0 0 0 0 0 31
- @ 0 0 0 0 0 0 0 0 32
- @
- @
- @ (2) MUST be defined in 'cpu_a.asm' (or 'cpu_c.c') if CPU_CFG_TRAIL_ZEROS_ASM_PRESENT is
- @ #define'd in 'cpu_cfg.h' or 'cpu.h'.
- @********************************************************************************************************
-
- .thumb_func
- CPU_CntTrailZeros:
- RBIT R0, R0 @ Reverse bits
- CLZ R0, R0 @ Count trailing zeros
- BX LR
-
-
- @********************************************************************************************************
- @ CPU_RevBits()
- @ REVERSE BITS
- @
- @ Description : Reverses the bits in a data value.
- @
- @ Prototypes : CPU_DATA CPU_RevBits(CPU_DATA val);
- @
- @ Argument(s) : val Data value to reverse bits.
- @
- @ Return(s) : Value with all bits in 'val' reversed (see Note #1).
- @
- @ Caller(s) : Application.
- @
- @ This function is an INTERNAL CPU module function but MAY be called by application function(s).
- @
- @ Note(s) : (1) The final, reversed data value for 'val' is such that :
- @
- @ 'val's final bit 0 = 'val's original bit N
- @ 'val's final bit 1 = 'val's original bit (N - 1)
- @ 'val's final bit 2 = 'val's original bit (N - 2)
- @
- @ ... ...
- @
- @ 'val's final bit (N - 2) = 'val's original bit 2
- @ 'val's final bit (N - 1) = 'val's original bit 1
- @ 'val's final bit N = 'val's original bit 0
- @********************************************************************************************************
-
- .thumb_func
- CPU_RevBits:
- RBIT R0, R0 @ Reverse bits
- BX LR
-
-
- @********************************************************************************************************
- @ CPU ASSEMBLY PORT FILE END
- @********************************************************************************************************
-
- .end
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