Core CSR Register Access
Click Nuclei Core CSR to learn about Core CSR in Nuclei ISA Spec.
- group NMSIS_Core_CSR_Register_Access
Functions to access the Core CSR Registers.
The following functions or macros provide access to Core CSR registers.
Defines
-
__RV_CSR_SWAP(csr, val)
CSR operation Macro for csrrw instruction.
Read the content of csr register to __v, then write content of val into csr register, then return __v
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
val – value to store into the CSR register
- Returns
the CSR register value before written
-
__RV_CSR_READ(csr)
CSR operation Macro for csrr instruction.
Read the content of csr register to __v and return it
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
- Returns
the CSR register value
-
__RV_CSR_WRITE(csr, val)
CSR operation Macro for csrw instruction.
Write the content of val to csr register
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
val – value to store into the CSR register
-
__RV_CSR_READ_SET(csr, val)
CSR operation Macro for csrrs instruction.
Read the content of csr register to __v, then set csr register to be __v | val, then return __v
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
val – Mask value to be used wih csrrs instruction
- Returns
the CSR register value before written
-
__RV_CSR_SET(csr, val)
CSR operation Macro for csrs instruction.
Set csr register to be csr_content | val
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
val – Mask value to be used wih csrs instruction
-
__RV_CSR_READ_CLEAR(csr, val)
CSR operation Macro for csrrc instruction.
Read the content of csr register to __v, then set csr register to be __v & ~val, then return __v
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
val – Mask value to be used wih csrrc instruction
- Returns
the CSR register value before written
-
__RV_CSR_CLEAR(csr, val)
CSR operation Macro for csrc instruction.
Set csr register to be csr_content & ~val
- Parameters
csr – CSR macro definition defined in Core CSR Registers, eg. CSR_MSTATUS
val – Mask value to be used wih csrc instruction
Functions
- __STATIC_FORCEINLINE void __switch_mode (uint8_t mode, uintptr_t stack, void(*entry_point)(void))
switch privilege from machine mode to others.
Execute into entry_point in mode(supervisor or user) with given stack
- Parameters
mode – privilege mode
stack – predefined stack, size should set enough
entry_point – a function pointer to execute
- __STATIC_FORCEINLINE void __enable_irq (void)
Enable IRQ Interrupts.
Enables IRQ interrupts by setting the MIE-bit in the MSTATUS Register.
Remark
Can only be executed in Privileged modes.
- __STATIC_FORCEINLINE void __disable_irq (void)
Disable IRQ Interrupts.
Disables IRQ interrupts by clearing the MIE-bit in the MSTATUS Register.
Remark
Can only be executed in Privileged modes.
- __STATIC_FORCEINLINE void __enable_irq_s (void)
Enable IRQ Interrupts in supervisor mode.
Enables IRQ interrupts by setting the SIE-bit in the SSTATUS Register.
Remark
Can only be executed in Privileged modes.
- __STATIC_FORCEINLINE void __disable_irq_s (void)
Disable IRQ Interrupts in supervisor mode.
Disables IRQ interrupts by clearing the SIE-bit in the SSTATUS Register.
Remark
Can only be executed in Privileged modes.
- __STATIC_FORCEINLINE uint64_t __get_rv_cycle (void)
Read whole 64 bits value of mcycle counter.
This function will read the whole 64 bits of MCYCLE register
Remark
It will work for both RV32 and RV64 to get full 64bits value of MCYCLE
- Returns
The whole 64 bits value of MCYCLE
- __STATIC_FORCEINLINE uint64_t __get_rv_instret (void)
Read whole 64 bits value of machine instruction-retired counter.
This function will read the whole 64 bits of MINSTRET register
Remark
It will work for both RV32 and RV64 to get full 64bits value of MINSTRET
- Returns
The whole 64 bits value of MINSTRET
- __STATIC_FORCEINLINE uint64_t __get_rv_time (void)
Read whole 64 bits value of real-time clock.
This function will read the whole 64 bits of TIME register
Remark
It will work for both RV32 and RV64 to get full 64bits value of TIME
- Attention
only available when user mode available
- Returns
The whole 64 bits value of TIME CSR
- __STATIC_FORCEINLINE unsigned long __get_cluster_id (void)
Get cluster id of current cluster.
This function will get cluster id of current cluster in a multiple cluster system
Remark
mhartid bit 15-8 is designed for cluster id in nuclei subsystem reference design
- Attention
function is allowed in machine mode only
- Returns
The cluster id of current cluster
- __STATIC_FORCEINLINE unsigned long __get_hart_index (void)
Get hart index of current cluster.
This function will get hart index of current cluster in a multiple cluster system, hart index is hartid - hartid offset, for example if your hartid is 1, and offset is 1, then hart index is 0
- Attention
function is allowed in machine mode only
- Returns
The hart index of current cluster
- __STATIC_FORCEINLINE unsigned long __get_hart_id (void)
Get hart id of current cluster.
This function will get hart id of current cluster in a multiple cluster system
Remark
it will return full hartid not part of it for reference subsystem design, if your reference subsystem design has hartid offset, please define __HARTID_OFFSET in <Device>.h
- Attention
function is allowed in machine mode only
- Returns
The hart id of current cluster
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__RV_CSR_SWAP(csr, val)