_MUL
#define DEFAULTSTKSZ _MUL(DEFAULTSTKSZ_NPGS, PAGESIZE) /* as(1) lameness */
subq $_CONST(_MUL(XMM_SIZE, nreg)), %rsp; \
addq $_CONST(_MUL(XMM_SIZE, nreg)), %rsp
subl $_CONST(_MUL(XMM_SIZE, nreg) + XMM_ALIGN), %esp; \
addl $_CONST(_MUL(XMM_SIZE, nreg) + XMM_ALIGN), %esp;