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procedures:task_addressing [2011/07/23 14:55]
scott created
procedures:task_addressing [2011/07/23 15:39] (current)
scott
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 indirect pointers to the actual base and limit pairs. indirect pointers to the actual base and limit pairs.
  
-The smallest allocatable unit of memory is a Memory Area It may be from 1,000 to 1,000,000 digits in size, in increments of 1,000 digits.+A memory area is the smallest allocatable unit of memory. It can be from 
 +1000 to 1000000 digits in length, in 1000-digit increments. For example, 
 +a software code module that is 57244 digits in length is assigned a 
 +58000-digit memory area. A software code module of 150 is digits assigned 
 +a 1000-digit memory area. 
 + 
 +A memory area is located by a base and limit pair contained in a MAT 
 +entry. For references to data or code in the local addressing 
 +environment, the base relative memory addresses are added to the selected 
 +base value to determine the absolute memory location. 
 + 
 +Memory is accessible only after the processor compares the base and limit 
 +values to the requested memory access address, and determines that the 
 +address is less than the limit value but greater than or equal to the 
 +base value. If the address is outside of the specified memory area, an 
 +address error (AEX=20-26) occurs and the instruction terminates without 
 +storing any more data into memory. 
 + 
 +Every task has a memory area (located by user EN 0, memory area number 0) 
 +called the MCP data area, where the MCP maintains information about that 
 +task. This area also contains the reserved memory of the MCP routines for 
 +that task (see [[processor_state:mcp_data_area|Reserved Memory Relative to the MCP Data Area]]). The MCP Data Area is described by the base and limit pair #0 when a 
 +task is executing MCP code.
  
 The following instructions or procedures change the processor operating The following instructions or procedures change the processor operating
procedures/task_addressing.txt · Last modified: 2011/07/23 15:39 by scott
 
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