參數(shù)資料
型號(hào)： TS68020DESC03XC
廠商： ATMEL CORP
元件分類： 微控制器/微處理器
英文描述： HCMOS 32-bit Virtual Memory Microprocessor
中文描述： 32-BIT, 20 MHz, MICROPROCESSOR, CPGA114
封裝： CERAMIC, PGA-114
文件頁(yè)數(shù)： 32/45頁(yè)
文件大?。?/td> 1256K
代理商： TS68020DESC03XC
32
TS68020
2115A–HIREL–07/02
Multi-processing
To further support multi-processing with the TS68020, a compare and swap instruction,
CAS, has been added. This instruction makes use of the read-modify-write cycle to
compare two operands and swap a third operand pending the results of the compare. A
variant of this instruction, CAS2, performs similarly comparing dual operand pairs, and
updating two operands.
These multi-processing operations are useful when using common memory to share or
pass data between multiple processing elements. The read-modify-write cycle is an indi-
visible operand that allows reading and updating a “l(fā)ock” operand used to control
access to the common memory elements. The CAS2 instruction is more powerful since
dual operands allow the “l(fā)ock” to the checked and two values (i.e., both pointers in a
doubly-linked list) to be updated according to the lock’s status, all in a single operation.
Module Support
The TS68020 includes support for modules with the call module (CALLM) and return
from module (RTM) instructions. The CALLM instruction references a module descrip-
tor. This descriptor contains control information for entry into the associated module.
The CALLM instruction creates a module stack frame and stores the module state in
that frame. The RTM instruction recovers the previous module state from the stack
frame and returns to the calling module.
The module interface also provides a mechanism for finer resolution of access control
by external hardware. Although the TS68020 does not interrupt the access control infor-
mation, it does communicate with external hardware when the access control is to be
changed, and relies on the external hardware to verify that the changes are legal.
CALLM and RTM, when used as subroutine calls and returns with proper descriptor for-
mats, cause the TS68020 to perform the necessary actions to verify legitimate access to
modules.
Virtual Memory/Machine
Concepts
The full addressing range of the TS68020 is 4-Gbyte (4, 294, 967, 296). However, most
TS68020 systems implement a smaller physical memory. Nonetheless, by using virtual
memory techniques, the system can be made to appear to have a full 4-Gbyte of physi-
cal memory available to each user program. These techniques have been used for
many years in large mainframe computers and minicomputers. With the TS68020 (as
with the TS68010 and TS68012), virtual memory can be fully supported in microproces-
sor-based systems.
In a virtual memory system, a user program can be written as though it has a large
amount of memory available to it when actually only a smaller amount of memory is
physically present in the system. In a similar fashion, a system provides user programs
access to other devices that are not physically present in the system, such as tape
drives, disk drives, printers, or terminals. With proper software emulation, a physical
system can be made to appear to a user program as any other 68000 computer system
and the program may be given full access to all of the resources of that emulated sys-
tem. Such an emulator system is called a virtual machine.
Virtual Memory
The basic mechanism for supporting virtual memory is to provides a limited amount of
high-speed physical memory that can be accessed directly by the processor while main-
taining of a much larger “virtual” memory on secondary storage devices such as large
capacity disk drives. When the processor attempts to access a location in the virtual
memory map that is not resident in the physical memory (referred to as a page fault), the
access to that location is temporarily suspended while the necessary data is fetched
from secondary storage and placed in physical memory; the suspended access is then
either restarted or continued.
相關(guān)PDF資料
PDF描述
TS68020DESC03YA HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC03YC HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC04XA HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC04XC HCMOS 32-bit Virtual Memory Microprocessor
TS68020MF16 HCMOS 32-bit Virtual Memory Microprocessor
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TS68020DESC03YA 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC03YC 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC04XA 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC04XC 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:HCMOS 32-bit Virtual Memory Microprocessor
TS68020DESC04YA 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:HCMOS 32-bit Virtual Memory Microprocessor
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