A, reference
wiki pdp-11 architecture
Two, noun explanation
ISA, Instruction Set Architecture, DEC, Digital Equipment Corporation, Central Processing Units, Microprocessor, Minicomputer, PC, Program Counter, SP, Stack Pointer, PSW, A) processor status word B) processor status word
Third, the body
1. The memory
1.1 Data format
1.2 Memory management
1.3 Memory expansion
2. Register
The CPU contains eight universal 16-bit registers, called R0, R1, R2, R3, R4, R5, R6, and R7. The register R7 is a program counter (PC), although any register can be used as a stack pointer, But R6 is the stack pointer (SP) for hardware interrupts and traps, and R5 is typically used to point to the current procedure call frame. To speed up context switching, some PDP-11 models provide dual R1-R5 register sets, kernel, supervisor (if any), and normal user mode, with separate memory maps and separate stack Pointers (so that user programs don’t fail by storing invalid values in the stack pointer register).