gcc - Need explanation of ARM Cortex-M3 assembly instruction in CMSIS to __set_PRIMASK -

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below code snippet arm cmsis library used set value of primask register.

/**  * @brief  set priority mask value  *  * @param  primask  primask  *  * set priority mask bit in priority mask register  */ static __inline void __set_primask(uint32_t primask) {    register uint32_t __regprimask         __asm("primask");    __regprimask = (primask); }

the part don't understand inline assembly instruction

__asm("primask");

i haven't read addressing registers name in way. how can have inline assembly without op-code first? assigning __regprimask register location? can point reference document?

register uint32_t __regprimask __asm("primask");

...is declaration of local register variable called __regprimask stored in primask register.

in other words, assigning register variable set value of register primask.


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