In the user mode, a group of privileged instructions are illegal, and only 47 of the 128 program-addressable, ... The mode is determined by the contents of an unaddressable register, the processor state register (PSR), which can be set by oneanbsp;...
|Title||:||A Laboratory Manual for Compiler and Operating System Inplementation|
|Author||:||Maurice Howard Halstead|
|Publisher||:||North Holland - 1974|