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Section 2 CPU
Rev. 4.00 Sep. 14, 2005 Page 81 of 982
REJ09B0023-0400
2.6
DSP Extended-Function Instructions
2.6.1 Introduction
The newly added instructions are classified into the following three groups:
1. Additional system control instructions for the CPU unit
2. DSP unit memory-register single and double data transfer
3. DSP unit parallel processing
Group 1 instructions are provided to support loop control and data transfer between CPU core
registers or memory and new control registers added to the CPU core. DSP operations employ a
multi-level nested-loop structure. With a single-level loop, use of the decrement and test, DTRn,
and conditional delayed branch BF/S instructions supported by the SH-3 is adequate. However,
with nested loops, DSP performance can be improved by means of a zero-overhead loop control
function.
The RS, RE, and MOD registers have been added to support loop control and modulo addressing
functions. Instructions are supported for data transfer between these new control registers and
general registers or memory. In addition, the LDRS and LDRE address calculation registers have
been added to reduce the code size for the initial settings for zero-overhead loop control.
An independent control register, DSR, is provided for the DSP engine. This register is treated as a
system register such as MACL and MACH. The A0, X0, X1, Y0, and Y1 registers are treated as
system registers from the CPU side, and LDS/STS instructions are supported for the same
purpose. Table 2.25 shows the instruction code map for the new system control instructions for the
CPU core.
Group 2 instructions are provided to reduce DSP operation program code size. Data transfer
instructions that perform no data processing are frequently executed by the DSP engine. In this
case, a 32-bit instruction code is unnecessarily long, and wastes space in the program memory
area. All instructions in this class have a 16-bit code length, the same as conventional SH core
instructions. Single data transfer instructions have greater flexibility in terms of operands than the
double data transfer instruction or parallel instruction class.
Group 3 instructions are provided for fast execution of digital signal processing operations using
the DSP unit. These instructions have a 32-bit instruction code, so that a maximum of four
instructions—an ALU operation, multiplication, and two data transfer instructions—can be
executed in parallel.
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...