Re: VAX architectural critiques - Re: VAX RPB (Restart Parameter Block)

[Matt Thomas <matt%3am-software.com@localhost>]

On Feb 6, 2013, at 6:25 PM, Toby Thain wrote:

> Least-significant-bit instructions would have seemed useful at the time to 
> implement a Pascal-ish *Boolean* (*not* a C "boolean" test - C hadn't 
> dominated the semantics of everything yet).

You are looking through a unix-tinted looking glass which is incorrect.
Remember the VAX was designed to implement VMS and VMS uses the least
significant bit to indicate success / failure on return status, and that
is what the BLB[CS] instruction was designed for.