PROGRAMMING MODEL
MOTOROLA
PROGRAM CONTROL UNIT
5 - 9
This special-purpose address register is stacked when program looping is initialized,
when a JSR is performed, or when interrupts occur (except for no-overhead fast
interrupts).
5.4.2 Status Register
The 16-bit SR consists of a mode register (MR) in the high-order eight bits and a condition
code register (CCR) in the low-order eight bits, as shown in Figure 5-5. The SR is stacked
when program looping is initialized, when a JSR is performed, or when interrupts occur,
(except for no-overhead fast interrupts).
The MR is a special purpose control register which defines the current system state of the
processor. The MR bits are affected by processor reset, exception processing, the DO,
end current DO loop (ENDDO), return from interrupt (RTI), and SWI instructions and by
instructions that directly reference the MR register, such as OR immediate to control reg-
ister (ORI) and AND immediate to control register (ANDI). During processor reset, the
interrupt mask bits of the MR will be set. The scaling mode bits, loop flag, and trace bit will
be cleared.
All bits are cleared after hardware reset except bits 8 and 9 which are set to ones.
15
14
13
12
11 10
9
8
7
6
5
4
3
2
1
0
MR
CCR
*
LF DM
T
S1
S0
I1
I0
S
L
E
U
N
Z
V
C
Figure 5-5 Status Register Format
CARRY
OVERFLOW
ZERO
NEGATIVE
UNNORMALIZED
EXTENSION
LIMIT
SCALING
INTERRUPT MASK
SCALING MODE
RESERVED
TRACE MODE
DOUBLE PRECISION
MULTIPLY MODE
LOOP FLAG
Bits 12 and 16 to 23 are reserved, read as zero and should be written with zero for future compatibility
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 ...