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Section 3 DSP Operation
Rev. 4.00 Sep. 14, 2005 Page 111 of 982
REJ09B0023-0400
Overflow Protection: The S bit in SR is also effective for arithmetic shift operation in the DSP
unit. See section 3.1.8, Overflow Protection, for details.
Logical Shift: Figure 3.10 shows the logical shift operation flow.
DSR
GT
Z
N
V
DC
Updated
7g
0g 31
16 15
0
Sy
7g
0g 31
16 15
0
Shift out
Shift out
0
0
Cleared
Left Shift
Right Shift
7g
0g 31
22 21 16
Imm2
5
0
15
0
Shift amount data:
(Source 2)
> =
0
<
0
+16 to –16
Ignored
Figure 3.10 Logical Shift Operation Flow
As shown in figure 3.10, the logical shift operation uses the upper word of the source 1 operand
and the destination operand. The lower word and guard-bit parts are ignored for the source
operand and those of the destination operand are automatically cleared as in the ALU logical
operations. The shift amount is specified by the source 2 operand as an integer data. The source 2
operand can be specified by either the register or immediate operand. The available shift range is
from –16 to +16. Here, a negative value means the right shift, and a positive value means the left
shift. It is possible for any source 2 operand to specify from –32 to +31, but the result is unknown
if an invalid shift value is specified. In case of a shift with an immediate operand instruction, the
source 1 operand must be the same register as the destination's. These operations are executed in
the DSP stage, as shown in figure 3.2. The DSP stage is the same stage as the MA stage in which
memory access is performed.
Every time a logical shift operation is executed, the DC, N, Z, V and GT bits in DSR are basically
updated in accordance with the operation result. In case of a conditional operation, they are not
updated even though the specified condition is true and the operation is executed. In case of an
unconditional operation, they are always updated in accordance with the operation result. The
definition of the DC bit is selected by the CS0 to CS2 (condition selection) bits in DSR. The DC
bit result is:
Содержание HD6417641
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Страница 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
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Страница 204: ...Section 4 Clock Pulse Generator CPG Rev 4 00 Sep 14 2005 Page 154 of 982 REJ09B0023 0400...
Страница 212: ...Section 5 Watchdog Timer WDT Rev 4 00 Sep 14 2005 Page 162 of 982 REJ09B0023 0400...
Страница 228: ...Section 6 Power Down Modes Rev 4 00 Sep 14 2005 Page 178 of 982 REJ09B0023 0400...
Страница 246: ...Section 8 X Y Memory Rev 4 00 Sep 14 2005 Page 196 of 982 REJ09B0023 0400...
Страница 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Страница 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Страница 500: ...Section 13 Direct Memory Access Controller DMAC Rev 4 00 Sep 14 2005 Page 450 of 982 REJ09B0023 0400...
Страница 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Страница 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Страница 734: ...Section 18 Multi Function Timer Pulse Unit MTU Rev 4 00 Sep 14 2005 Page 684 of 982 REJ09B0023 0400...
Страница 868: ...Section 21 A D Converter Rev 4 00 Sep 14 2005 Page 818 of 982 REJ09B0023 0400...
Страница 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
Страница 956: ...Section 24 List of Registers Rev 4 00 Sep 14 2005 Page 906 of 982 REJ09B0023 0400...
Страница 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Страница 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
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Страница 1036: ...SH7641 Hardware Manual...