RE : Re: [RFC] Program Bounds Checking

2006-09-29 Thread Etienne Lorrain
--- Robert Dewar <[EMAIL PROTECTED]> wrote: > Tzi-cker Chiueh wrote: > > We have considered the bound instruction in the CASH project. But > > we found that bound instruction is slower than the six normal > > instructions it is meant to replace for range checking. For example, the > > bound instruc

Re: [RFC] Program Bounds Checking

2006-09-28 Thread Robert Dewar
Tzi-cker Chiueh wrote: We have considered the bound instruction in the CASH project. But we found that bound instruction is slower than the six normal instructions it is meant to replace for range checking. For example, the bound instruction on a 1.1 GHz PIII machine requires 7-8 clock cycles whi

Re: [RFC] Program Bounds Checking

2006-09-28 Thread Joe Buck
On Thu, Sep 28, 2006 at 12:52:18PM -0400, Tzi-cker Chiueh wrote: > We have considered the bound instruction in the CASH project. But > we found that bound instruction is slower than the six normal > instructions it is meant to replace for range checking. For example, the > bound instruction on a 1.

Re: [RFC] Program Bounds Checking

2006-09-28 Thread Nicholas Nethercote
On Thu, 28 Sep 2006, Tzi-cker Chiueh wrote: We have considered the bound instruction in the CASH project. But we found that bound instruction is slower than the six normal instructions it is meant to replace for range checking. For example, the bound instruction on a 1.1 GHz PIII machine require

Re: [RFC] Program Bounds Checking

2006-09-28 Thread Tzi-cker Chiueh
We have considered the bound instruction in the CASH project. But we found that bound instruction is slower than the six normal instructions it is meant to replace for range checking. For example, the bound instruction on a 1.1 GHz PIII machine requires 7-8 clock cycles while the 6 equivalent inst

Re: [RFC] Program Bounds Checking

2006-09-28 Thread Etienne Lorrain
You write you needs 6 assembly instructions to check a pointer on x86, I am using the "bound" ia32 instruction (1 byte opcode 0x62, invalid in ia64) to check the stack pointer for few years now in Gujin (http://gujin.org) without problem. I am doing this kind of thing to guard against stack