PROGRAMMING MODEL
5 - 12
PROGRAM CONTROL UNIT
MOTOROLA
5.4.2.9
Interrupt Masks (Bits 8 and 9)
The interrupt mask bits, I1 and I0, reflect the current IPL of the processor and indicate
the IPL needed for an interrupt source to interrupt the processor. The current IPL of the
processor can be changed under software control. The interrupt mask bits are set during
hardware reset but not during software reset.
5.4.2.10
Scaling Mode (Bits 10 and 11)
The scaling mode bits, S1 and S0, specify the scaling to be performed in the data ALU
shifter/limiter, and also specify the rounding position in the data ALU multiply-accumula-
If
S1=0 and S0=0 (no scaling)
then S = (A46 XOR A45) OR (B46 XOR B45)
If
S1=0 and S0=1 (scale down)
then S = (A47 XOR A46) OR (B47 XOR B46)
If
S1=1 and S0=0 (scale up)
then S = (A45 XOR A44) OR (B45 XOR B44)
If
S1=1 and S0=1 (reserved)
then the S flag is undefined.
where Ai and Bi means bit i in accumulator A or B.
I1
I0
Exceptions Permitted
Exceptions Masked
0
0
IPL 0,1,2,3
None
0
1
IPL 1,2,3
IPL 0
1
0
IPL 2,3
IPL 0,1
1
1
IPL 3
IPL 0,1,2
Summary of Contents for DSP56K
Page 12: ...xii LIST of TABLES MOTOROLA List of Tables Continued Table Page Number Title Number ...
Page 13: ...MOTOROLA DSP56K FAMILY INTRODUCTION 1 1 SECTION 1 DSP56K FAMILY INTRODUCTION ...
Page 31: ...MOTOROLA DATA ARITHMETIC LOGIC UNIT 3 1 SECTION 3 DATA ARITHMETIC LOGIC UNIT ...
Page 50: ...DATA ALU SUMMARY 3 20 DATA ARITHMETIC LOGIC UNIT MOTOROLA ...
Page 51: ...MOTOROLA ADDRESS GENERATION UNIT 4 1 SECTION 4 ADDRESS GENERATION UNIT ...
Page 77: ...MOTOROLA PROGRAM CONTROL UNIT 5 1 SECTION 5 PROGRAM CONTROL UNIT ...
Page 124: ...INSTRUCTION GROUPS 6 30 INSTRUCTION SET INTRODUCTION MOTOROLA ...
Page 125: ...MOTOROLA PROCESSING STATES 7 1 SECTION 7 PROCESSING STATES STOP WAIT EXCEPTION NORMAL RESET ...
Page 167: ...STOP PROCESSING STATE MOTOROLA PROCESSING STATES 7 43 ...
Page 168: ...STOP PROCESSING STATE 7 44 PROCESSING STATES MOTOROLA ...
Page 169: ...MOTOROLA PORT A 8 1 SECTION 8 PORT A ...
Page 176: ...PORT A INTERFACE 8 8 PORT A MOTOROLA ...
Page 177: ...MOTOROLA PLL CLOCK OSCILLATOR 9 1 SECTION 9 PLL CLOCK OSCILLATOR x x d Φ VCO ...
Page 191: ...10 2 ON CHIP EMULATION OnCE MOTOROLA SECTION 10 ON CHIP EMULATION OnCE ...
Page 218: ...USING THE OnCE MOTOROLA ON CHIP EMULATION OnCE 10 29 ...
Page 604: ...INSTRUCTION ENCODING A 338 INSTRUCTION SET DETAILS MOTOROLA ...
Page 605: ...MOTOROLA BENCHMARK PROGRAMS B 1 APPENDIX B BENCHMARK PROGRAMS T T T T T P1 P3 P2 P4 T T T ...
Page 609: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 5 ...
Page 611: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 7 ...
Page 613: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 9 ...
Page 615: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 11 ...