MC68030RC25C Freescale Semiconductor, MC68030RC25C Datasheet - Page 385

• Manufacturer Part Number: MC68030RC25C
• Description: IC MPU 32BIT ENHANCED 128-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68030RC25C

• Processor Type: M680x0 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 128-PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

9-84
/* Paging Bus Error Handler for example O.S.
/* Use MC68030 PTEST instruction to get fault status and table entry
/* Global Variables to all code
case PTEST (BusErrAddress,TableEntry) of
Procedure BusErrorHandler (BusErrAddress);
Declare TableEntry;
T h e e x a m p l e bus e r r o r e x c e p t i o n r o u t i n e is c a l l e d B u s E r r o r H a n d l e r . It is m o r e
g e n e r a l t h a n V a l l o c a t e b e c a u s e it r e l i e s o n s e v e r a l o p e r a t i n g - s y s t e m -
d e p e n d e n t items. T h e v a r i a b l e p o i n t e r V i c t i m T a s k is a s s u m e d to p o i n t to a
t a b l e f r o m a task t h a t is l o s i n g a p a g e f r a m e . T h i s a s s u m p t i o n is n e c e s s a r y
f u r t h e r s i m p l i f i e d by o m i t t i n g t h e f u n c t i o n c o d e v a l u e a n d t h e r e a d / w r i t e
status, w h i c h d o n o t affect t h e basic l o g i c of t h e p r o g r a m .
b e c a u s e c o n t r o l block l a y o u t and t h e m e t h o d o f s e a r c h i n g f o r a n d f i n d i n g
o t h e r tasks in t h e e x a m p l e o p e r a t i n g s y s t e m are n o t d e f i n e d . T h e c o d e is
r supervisor violation - task tried accessing restricted memory
/* Write Protected - tried writing into read-only memory
r Limit Violation - tried accessing Unmapped virtual space. This happens in our example
/* O.S. when accessing within a 16 megabyte segment in User memory past what is
/* currently allocated for the lower page table as determined by the upper level limit field.
/* Invalid - pointer indicates invalid. Must determine status.
/* Bus Error - translation table is invalid or memory hardware problems. Terminate the task.
S: AbortTask("Attempted access of Supervisor-only memory");
W: AbortTask("Attempted write into read-only memory");
L: AbortTask("lnvalid address");
I: begin
B: AbortTask("lnvalid table or memory hardware error");
/* If upper level entry then that 16 Meg chunk of the virtual space is unallocated
/* and has no page tables.
/* We are at a page table entry. Look at software flags.
/* If this page unallocated to the User then abort task
/* If this page is virgin then assign to it a physical frame
If TableEntry is upper level then AbortTask("lnvalid address");
if EntryStatus --- invalid_virgin then do
If EntryStatus=invalid_unallocated then
GetFrame(TableEntry);
PLOAD (BusErrAddress);
exit BusErrorl-landler;
end do;
MC68030 USER'S MANUAL
AbortTask("lnvalid Address");
/*Pointer returned by PTEST instruction
/* pointing to the lowest level entry in the
/* translation tables.
/* address returned in entry
r done so continue task
/* update MC68030 entry
MOTOROLA
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/
*/