27 Jun
2014
27 Jun
'14
7:23 a.m.
On Fri, Jun 27, 2014 at 1:14 PM, Simon Marlow
The problem is that this instruction requires three separate registers, but cmpxchgl already reads and writes %eax leaving only two free registers (%ecx and %edx).
You'll need to arrange to not use the complicated addressing modes with cmpxchg on i386, and keep the number of free regs required <= 2.
Where's the best place to arrange for that? If I switch from using getAmode to computing the address into a temp register in StgCmmPrim will that ensure that the address is simple, or could some optimization replace my temp register computation with a complex address again?