Section 2 CPU
Rev. 2.00 Mar 09, 2006 page 57 of 906
REJ09B0292-0200
3. Increment address registers: The Ax, Ay registers are address pointers. The value +2 is added
to each of them after the data transfer (post-update).
Each of the address pointers has an index register. The R8 register becomes the index register (Ix)
of the X memory address register (Ax), and the R9 register becomes the index register (Iy) of the
Y memory address register (Ay).
The X, Y data transfer instructions are processed in word lengths. X, Y data memory is accessed
in 16 bit lengths. This is why the increment processing adds 2 to the address registers. In order to
decrement, set –2 in the index register and designate add index register addressing. During X, Y
data addressing, only bits 1 to 15 of the address pointer are valid. Always write a 0 to bit 0 of the
address pointer and the index register during X, Y data addressing.
Figure 2.9 shows the X, Y data transfer addressing. When X memory and Y memory are accessed
using the X, Y bus, the upper word of Ax (R4 or R5) and Ay (R6 or R7) is ignored. The result of
@Ay+ and @Ay+Iy is stored in the lower word of Ay, and the upper word retains its original
value.
ALU
AU
*
R8[Ix]
R4[Ax]
R5[Ax]
R9[Iy]
R6[Ay]
R7[Ay]
+2 (INC)
+2 (INC)
+0 (No update)
+0 (No update)
Notes:
All three addressing methods (increment, index register addition (Ix, Iy), and
no update) are post-updating methods. To decrement the address pointer, set
the index register to –2 or –4.
*
Adder added for DSP addressing.
Figure 2.9 X, Y Data Transfer Addressing
Содержание SH7616
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Страница 132: ...Section 2 CPU Rev 2 00 Mar 09 2006 page 106 of 906 REJ09B0292 0200 ...
Страница 568: ...Section 12 16 Bit Free Running Timer FRT Rev 2 00 Mar 09 2006 page 542 of 906 REJ09B0292 0200 ...
Страница 582: ...Section 13 Watchdog Timer WDT Rev 2 00 Mar 09 2006 page 556 of 906 REJ09B0292 0200 ...
Страница 662: ...Section 14 Serial Communication Interface with FIFO SCIF Rev 2 00 Mar 09 2006 page 636 of 906 REJ09B0292 0200 ...
Страница 706: ...Section 16 Serial I O SIO Rev 2 00 Mar 09 2006 page 680 of 906 REJ09B0292 0200 ...
Страница 820: ...Section 19 Pin Function Controller PFC Rev 2 00 Mar 09 2006 page 794 of 906 REJ09B0292 0200 ...
Страница 932: ...Appendix D Package Dimensions Rev 2 00 Mar 09 2006 page 906 of 906 REJ09B0292 0200 ...
Страница 935: ...SH7616 Hardware Manual ...