Renesas SH7781 用户手册

下载
页码 1692
29.   User Break Controller (UBC) 
Rev.1.00  Jan. 10, 2008  Page 1479 of 1658 
REJ09B0261-0100 
 
29.3.6
 
Program Counter Value to be Saved 
When a break has occurred, the address of the instruction to be executed when the program 
restarts is saved in the SPC then the exception handling state is initiated. A unique instruction 
causing a break can be identified unless the data value is included in the match conditions.  
1.  When the instruction fetch cycle (before instruction execution) is specified as the match 
condition: 
The address of the instruction which has satisfied the match conditions is saved in the SPC. 
The instruction which has satisfied the match conditions is not executed, but a break occurs 
instead. However, if the match conditions are satisfied for the delayed slot instruction, the 
address of the delayed branch instruction is saved in the SPC.  
2.  When the instruction fetch cycle (after instruction execution) is specified as the match 
condition: 
The address of the instruction immediately after the instruction which has satisfied the match 
conditions is saved in the SPC. The instruction which has satisfied the match conditions is 
executed, then a break occurs before the next instruction. If the match conditions are satisfied 
for the delayed branch instruction or its delayed slot, these instructions are executed and the 
address of the branch destination is saved in the SPC.  
3.  When the operand access (address only) is specified as the match condition: 
The address of the instruction immediately after the instruction which has satisfied the break 
conditions is saved in the SPC. The instruction which has satisfied the match conditions are 
executed, then a break occurs before the next instruction. However, if the conditions are 
satisfied for the delayed slot, the address of the branch destination is saved in the SPC.  
4.  When the operand access (address and data) is specified as the match condition: 
If the data value is added to the match conditions, the instruction which has satisfied the match 
conditions is executed. A user break occurs before executing an instruction that is one through 
six instructions after the instruction which has satisfied the match conditions. The address of 
the instruction is saved in the SPC; thus, it is impossible to identify exactly where a break will 
occur. If the conditions are satisfied for the delayed slot instruction, the address of the branch 
destination is saved in the SPC. If a branch instruction follows the instruction which has 
satisfied the match conditions, a break may occur after the delayed instruction and delayed slot 
are executed. In this case, the address of the branch destination is also saved in the SPC.