PROGRAMMING MODEL
MOTOROLA
PROGRAM CONTROL UNIT
5 - 13
tor (MAC). The scaling modes are shown in the following table:
The scaling mode affects data read from the A or B accumulator registers out to the XDB
and YDB. Different scaling modes can occur with the same program code to allow dynam-
ic scaling. Dynamic scaling facilitates block floating-point arithmetic. The scaling mode
also affects the MAC rounding position to maintain proper rounding when different por-
tions of the accumulator registers are read out to the XDB and YDB. The scaling mode
bits, which are cleared at the start of a long interrupt service routine, are also cleared dur-
ing a processor reset.
5.4.2.11
Reserved Status (Bit 12)
This bits is reserved for future expansion and will read as zero during DSP read opera-
tions.
5.4.2.12
Trace Mode (Bit 13)
The trace mode (T) bit specifies the tracing function of the DSP56000/56001
only
. (With
other members of the DSP56K family, use the OnCE trace mode described in Section
10.5.) For the DSP56000/56001, if the T bit is set at the beginning of any instruction exe-
cution, a trace exception will be generated after the instruction execution is completed. If
the T bit is cleared, tracing is disabled and instruction execution proceeds normally. If a
long interrupt is executed during a trace exception, the SR with the trace bit set will be
stacked, and the trace bit in the SR is cleared (see SECTION 7 – PROCESSING
STATES for a complete description of a long interrupt operation). The T bit is also
cleared during processor reset.
5.4.2.13
Double Precision Multiply Mode (Bit 14)
The processor is in double precision multiply mode when this bit is set. (See Section 3.4
for detailed information on the double precision multiply mode.) When the DM bit is set,
the operations performed by the MPY and MAC instructions change so that a double
precision 48-bit by 48-bit double precision multiplication can be performed in six instruc-
S1
S0
Rounding
Bit
Scaling Mode
0
0
23
No Scaling
0
1
24
Scale Down (1-Bit Arithmetic Right Shift)
1
0
22
Scale Up (1-Bit Arithmetic Left Shift)
1
1
—
Reserved for Future Expansion
Содержание DSP56K
Страница 12: ...xii LIST of TABLES MOTOROLA List of Tables Continued Table Page Number Title Number ...
Страница 13: ...MOTOROLA DSP56K FAMILY INTRODUCTION 1 1 SECTION 1 DSP56K FAMILY INTRODUCTION ...
Страница 25: ...MOTOROLA DSP56K CENTRAL ARCHITECTURE OVERVIEW 2 1 SECTION 2 DSP56K CENTRAL ARCHITECTURE OVERVIEW ...
Страница 31: ...MOTOROLA DATA ARITHMETIC LOGIC UNIT 3 1 SECTION 3 DATA ARITHMETIC LOGIC UNIT ...
Страница 50: ...DATA ALU SUMMARY 3 20 DATA ARITHMETIC LOGIC UNIT MOTOROLA ...
Страница 51: ...MOTOROLA ADDRESS GENERATION UNIT 4 1 SECTION 4 ADDRESS GENERATION UNIT ...
Страница 77: ...MOTOROLA PROGRAM CONTROL UNIT 5 1 SECTION 5 PROGRAM CONTROL UNIT ...
Страница 124: ...INSTRUCTION GROUPS 6 30 INSTRUCTION SET INTRODUCTION MOTOROLA ...
Страница 125: ...MOTOROLA PROCESSING STATES 7 1 SECTION 7 PROCESSING STATES STOP WAIT EXCEPTION NORMAL RESET ...
Страница 167: ...STOP PROCESSING STATE MOTOROLA PROCESSING STATES 7 43 ...
Страница 168: ...STOP PROCESSING STATE 7 44 PROCESSING STATES MOTOROLA ...
Страница 169: ...MOTOROLA PORT A 8 1 SECTION 8 PORT A ...
Страница 176: ...PORT A INTERFACE 8 8 PORT A MOTOROLA ...
Страница 177: ...MOTOROLA PLL CLOCK OSCILLATOR 9 1 SECTION 9 PLL CLOCK OSCILLATOR x x d Φ VCO ...
Страница 191: ...10 2 ON CHIP EMULATION OnCE MOTOROLA SECTION 10 ON CHIP EMULATION OnCE ...
Страница 218: ...USING THE OnCE MOTOROLA ON CHIP EMULATION OnCE 10 29 ...
Страница 604: ...INSTRUCTION ENCODING A 338 INSTRUCTION SET DETAILS MOTOROLA ...
Страница 605: ...MOTOROLA BENCHMARK PROGRAMS B 1 APPENDIX B BENCHMARK PROGRAMS T T T T T P1 P3 P2 P4 T T T ...
Страница 606: ...SECTION CONTENTS B 2 BENCHMARK PROGRAMS MOTOROLA SECTION B 1 INTRODUCTION 3 SECTION B 2 BENCHMARK PROGRAMS 3 ...
Страница 609: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 5 ...
Страница 611: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 7 ...
Страница 613: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 9 ...
Страница 615: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 11 ...