MC68030RC33C Freescale Semiconductor, MC68030RC33C Datasheet - Page 367

• Manufacturer Part Number: MC68030RC33C
• Description: IC MPU 32BIT ENHANCED 128-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68030RC33C

• Processor Type: M680x0 32-Bit
• Speed: 33MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 128-PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

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9.9.2 Task M e m o r y Ma p Definition
translation tables for each task, resulting in reduced bus activity for table
The MC68030 provides several different means by which the supervisor can
system.
With the large address space of the MC68030, each individual user task or
to user data items by the operating system. Another advantage of this map-
file I/O handlers and arithmetic conversion packages can be written re-entrantly
The simplest example of a shared virtual address space system is one in
which each user and supervisor process is given a unique virtual address
where in that space. Only one translation table tree is required for the entire
system, but each task can have individual tables if desired. With the common
tree approach, the operating system can access any item of any task without
system only has to update the user program and user data pointers in the
task access to its own data only. This scheme has the advantages of simple
table management and easy sharing of common items by giving them the
same virtual address for all tasks in the system. This scheme might be ideal
for real-time systems that do not require more complexity in memory man-
accesses without maintaining a large number of supervisor pointers in the
searches.
access the user address spaces. The supervisor can access any user address,
space) instruction. Some systems provide a complete 4-Gbyte virtual memory
systems in a virtual machine environment must provide a complete map to
accurately emulate the full addressing range for the subordinate operating
all user tasks can share the address space with the operating system. One
method of performing this function is implemented in the example operating
system in the next section. Sharing the address space provides direct access
ping method is that tasks can easily share code: Common routines such as
and be restricted to read-only access from all user tasks in the system.
range within the single 4-Gbyte virtual address space. In other words, the
system has only one linear virtual address space; all processes run some-
modifying the root pointer. Otherwise, only the currently active task is im-
mediately accessible, which often is adequate. To switch tasks, the operating
highest level translation table indexed by the function code. This gives each
agement facilities.
regardless of how the virtual space is partitioned, with the MOVES (move
map for each task. Indeed, an operating system that runs other operating
MC68030 USER'S MANUAL
MOTOROLA