Section 2 CPU
Rev. 5.00 May 29, 2006 page 22 of 698
REJ09B0146-0500
T bit: The T bit in the status register (SR) is used to indicate the result of compare operations, and
is read as a TRUE/FALSE condition determining if a conditional branch is taken or not. To
improve processing speed, the T bit logic state is modified only by specific operations. An
example of how the T bit may be used in a sequence of operations is shown below.
ADD
#1, R0
; T bit not modified by ADD operation
CMP/EQ
R1, R0
; T bit set to 1 when R0
=
0
BT
TRGET
; branch taken to TRGET when T bit = 1 (R0 = 0)
Literals: Byte-length literals are inserted directly into the instruction code as immediate data. To
maintain the 16-bit fixed-length instruction code, word or longword literals are stored in a table in
main memory rather than inserted directly into the instruction code. The memory table is accessed
by the MOV instruction using PC-relative addressing with displacement, as follows:
MOV.W
@(disp, PC), R0
Absolute Addresses: As with word and longword literals, absolute addresses must also be stored
in a table in main memory. The value of the absolute address is transferred to a register and the
operand access is specified by indexed register-indirect addressing, with the absolute address
loaded (like word and longword immediate data) during instruction execution.
16-Bit and 32-Bit Displacements: In the same way, 16-bit and 32-bit displacements also must be
stored in a table in main memory. Exactly like absolute addresses, the displacement value is
transferred to a register and the operand access is specified by indexed register-indirect addressing,
loading the displacement (like word and longword immediate data) during instruction execution.
Содержание SH7706 Series
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Страница 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Страница 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Страница 532: ...Section 16 Serial Communication Interface with FIFO SCIF Rev 5 00 May 29 2006 page 484 of 698 REJ09B0146 0500 ...
Страница 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Страница 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Страница 614: ...Section 21 User Debugging Interface H UDI Rev 5 00 May 29 2006 page 566 of 698 REJ09B0146 0500 ...
Страница 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Страница 749: ...SH7706 Group Hardware Manual ...