111 lines
3.7 KiB
ArmAsm
111 lines
3.7 KiB
ArmAsm
;-------------------------------------------------------------------------------
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; FILENAME: CyBootAsmRv.s
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; Version 3.40
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;
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; DESCRIPTION:
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; Assembly routines for RealView.
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;
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;-------------------------------------------------------------------------------
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; Copyright 2010-2013, Cypress Semiconductor Corporation. All rights reserved.
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; You may use this file only in accordance with the license, terms, conditions,
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; disclaimers, and limitations in the end user license agreement accompanying
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; the software package with which this file was provided.
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;-------------------------------------------------------------------------------
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AREA |.text|,CODE,ALIGN=3
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THUMB
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EXTERN Reset
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;-------------------------------------------------------------------------------
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; Function Name: CyDelayCycles
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;-------------------------------------------------------------------------------
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;
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; Summary:
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; Delays for the specified number of cycles.
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;
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; Parameters:
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; uint32 cycles: number of cycles to delay.
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;
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; Return:
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; None
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;
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;-------------------------------------------------------------------------------
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; void CyDelayCycles(uint32 cycles)
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ALIGN 8
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CyDelayCycles FUNCTION
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EXPORT CyDelayCycles
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; cycles bytes
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ADDS r0, r0, #2 ; 1 2 Round to nearest multiple of 4
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LSRS r0, r0, #2 ; 1 2 Divide by 4 and set flags
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BEQ CyDelayCycles_done ; 2 2 Skip if 0
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NOP ; 1 2 Loop alignment padding
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CyDelayCycles_loop
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SUBS r0, r0, #1 ; 1 2
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MOV r0, r0 ; 1 2 Pad loop to power of two cycles
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BNE CyDelayCycles_loop ; 2 2
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CyDelayCycles_done
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BX lr ; 3 2
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ENDFUNC
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;-------------------------------------------------------------------------------
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; Function Name: CyEnterCriticalSection
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;-------------------------------------------------------------------------------
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;
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; Summary:
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; CyEnterCriticalSection disables interrupts and returns a value indicating
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; whether interrupts were previously enabled (the actual value depends on
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; whether the device is PSoC 3 or PSoC 5).
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;
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; Note Implementation of CyEnterCriticalSection manipulates the IRQ enable bit
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; with interrupts still enabled. The test and set of the interrupt bits is not
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; atomic; this is true for both PSoC 3 and PSoC 5. Therefore, to avoid
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; corrupting processor state, it must be the policy that all interrupt routines
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; restore the interrupt enable bits as they were found on entry.
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;
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; Parameters:
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; None
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;
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; Return:
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; uint8
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; Returns 0 if interrupts were previously enabled or 1 if interrupts
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; were previously disabled.
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;
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;-------------------------------------------------------------------------------
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; uint8 CyEnterCriticalSection(void)
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CyEnterCriticalSection FUNCTION
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EXPORT CyEnterCriticalSection
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MRS r0, PRIMASK ; Save and return interrupt state
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CPSID I ; Disable interrupts
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BX lr
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ENDFUNC
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;-------------------------------------------------------------------------------
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; Function Name: CyExitCriticalSection
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;-------------------------------------------------------------------------------
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;
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; Summary:
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; CyExitCriticalSection re-enables interrupts if they were enabled before
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; CyEnterCriticalSection was called. The argument should be the value returned
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; from CyEnterCriticalSection.
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;
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; Parameters:
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; uint8 savedIntrStatus:
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; Saved interrupt status returned by the CyEnterCriticalSection function.
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;
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; Return:
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; None
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;
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;-------------------------------------------------------------------------------
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; void CyExitCriticalSection(uint8 savedIntrStatus)
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CyExitCriticalSection FUNCTION
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EXPORT CyExitCriticalSection
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MSR PRIMASK, r0 ; Restore interrupt state
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BX lr
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ENDFUNC
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END
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; [] END OF FILE
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