General Exceptions - Hitachi SH7750 Programming Manual

5.6.2

General Exceptions

(1) Data TLB Miss Exception
• Source: Address mismatch in UTLB address comparison
• Transition address: VBR + H'0000 0400
• Transition operations:
The virtual address (32 bits) at which this exception occurred is set in TEA, and the
corresponding virtual page number (22 bits) is set in PTEH [31:10]. ASID in PTEH indicates
the ASID when this exception occurred.
The PC and SR contents for the instruction at which this exception occurred are saved in SPC
and SSR.
Exception code H'040 (for a read access) or H'060 (for a write access) is set in EXPEVT. The
BL, MD, and RB bits are set to 1 in SR, and a branch is made to PC = VBR + H'0400.
To speed up TLB miss processing, the offset is separate from that of other exceptions.
Data_TLB_miss_exception()
{
TEA = EXCEPTION_ADDRESS;
PTEH.VPN = PAGE_NUMBER;
SPC = PC;
SSR = SR;
EXPEVT = read_access ? H'00000040 : H'00000060;
SR.MD = 1;
SR.RB = 1;
SR.BL = 1;
PC = VBR + H'00000400;
}
Rev. 2.0, 03/99, page 97 of 396