On Mon, Jul 02, 2018 at 01:30:14AM +0800, Guo Ren wrote: > +#ifdef CONFIG_CPU_HAS_LDSTEX > +ENTRY(csky_cmpxchg) > + USPTOKSP > + mfcr a3, epc > + INCTRAP a3 > + > + subi sp, 8 > + stw a3, (sp, 0) > + mfcr a3, epsr > + stw a3, (sp, 4) > + > + psrset ee > +1: > + ldex a3, (a2) > + cmpne a0, a3 > + bt16 2f > + mov a3, a1 > + stex a3, (a2) > + bez a3, 1b > +2: > + sync.is > + mvc a0 > + ldw a3, (sp, 0) > + mtcr a3, epc > + ldw a3, (sp, 4) > + mtcr a3, epsr > + addi sp, 8 > + KSPTOUSP > + rte > +END(csky_cmpxchg) > +#else Please explain... if the CPU has LDEX/STEX, then _why_ do you need this?
