Renesas R5S72621 Manual Do Utilizador

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Section 6   Exception Handling 
 
R01UH0134EJ0400  Rev. 4.00  
 
Page 133 of 2108 
Sep 24, 2014 
 
 
 
SH7262 Group, SH7264 Group 
Exception 
Source 
Timing of Source Detection and Start of Handling 
Instructions 
Trap instruction 
Starts from the execution of a TRAPA instruction. 
General illegal 
instructions  
Starts from the decoding of undefined code anytime except 
immediately after a delayed branch instruction (delay slot) 
(including FPU instructions and FPU-related CPU instructions 
in FPU module standby state). 
Slot illegal 
instructions  
Starts from the decoding of undefined code placed directly after 
a delayed branch instruction (delay slot) (including FPU 
instructions and FPU-related CPU instructions in FPU module 
standby state), of instructions that rewrite the PC, of 32-bit 
instructions, of the RESBANK instruction, of the DIVS 
instruction, or of the DIVU instruction. 
Integer division 
exceptions 
Starts when detecting division-by-zero exception or overflow 
exception caused by division of the negative maximum value 
(H'80000000) by 
1. 
Instructions 
FPU exceptions 
Starts when detecting invalid floating point operation exception 
defined by IEEE standard 754, division-by-zero exception, 
overflow, underflow, or inexact exception. 
Also starts when qNaN or 
 is input to the source for a floating 
point operation instruction when the QIS bit in FPSCR is set. 
 
When exception handling starts, the CPU operates as follows: 
(1)  Exception Handling Triggered by Reset 
The initial values of the program counter (PC) and stack pointer (SP) are fetched from the 
exception handling vector table (PC and SP are respectively the H'00000000 and H'00000004 
addresses for power-on resets and the H'00000008 and H'0000000C addresses for manual resets). 
See section 6.1.3, Exception Handling Vector Table, for more information. The vector base 
register (VBR) is then initialized to H'00000000, the interrupt mask level bits (I3 to I0) of the 
status register (SR) are initialized to H'F (B'1111), and the BO and CS bits are initialized to 0. The 
BN bit in IBNR of the interrupt controller is also initialized to 0. The floating point status/control 
register (FPSCR) is initialized to H'00040001 by a power-on reset. The program begins running 
from the PC address fetched from the exception handling vector table.