RISC load-store verses x86 Add from memory.
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From: Andy 'Krazy' Glew on 1 Jul 2010 22:47 On 7/1/2010 12:57 PM, Tim McCaffrey wrote: > In article > <30028ecd-f025-4c05-bd8a-93c99e00a8a8(a)a30g2000yqn.googlegroups.com>, > MitchAlsup(a)aol.com says... > >> No assumption is needed on 1s-complement or 2s-complement machines. >> {Does anyone know of a machine using integer signed-magnitude that is >> still existing?} >> > > Why, yes, the Unisys Clearpath Libra systems. > (aka. MCP systems). Are these still being built and sold? New designs? Native hardware? Or, emulated on top of x86es. > > > And they do all this stuff. > > Bounds checking. > Integer overflow detection. > > and (x+c)< x will never work on an MCP system. Except in C, because the > compiler emulates 2s-complement. > > - Tim >
From: Andy Mountford on 2 Jul 2010 09:38
On Thu, 01 Jul 2010 19:47:30 -0700, Andy 'Krazy' Glew <ag-news(a)patten-glew.net> wrote: >On 7/1/2010 12:57 PM, Tim McCaffrey wrote: >> In article >> <30028ecd-f025-4c05-bd8a-93c99e00a8a8(a)a30g2000yqn.googlegroups.com>, >> MitchAlsup(a)aol.com says... >> >>> No assumption is needed on 1s-complement or 2s-complement machines. >>> {Does anyone know of a machine using integer signed-magnitude that is >>> still existing?} >>> >> >> Why, yes, the Unisys Clearpath Libra systems. >> (aka. MCP systems). > >Are these still being built and sold? New designs? Yes and yes > >Native hardware? > Yes, at the top end. >Or, emulated on top of x86es. > Yes, at the bottom end > >> >> >> And they do all this stuff. >> >> Bounds checking. >> Integer overflow detection. >> >> and (x+c)< x will never work on an MCP system. Except in C, because the >> compiler emulates 2s-complement. >> >> - Tim >> Andy (Unisys support) |