PROGRAMMING MODEL
MOTOROLA
PROGRAM CONTROL UNIT
5 - 17
data (MOVEP) when SSL is specified as a source or destination).
5.4.5.3
Underflow Flag (Bit 5)
The underflow flag is set when a stack underflow occurs. The underflow flag is a “sticky
bit” when the stack error flag is set. That is, when the stack error flag is set, the underflow
flag will not change state. The combination of “underflow=1” and “stack error=0” is an
illegal combination and will not occur unless it is forced by the user. If this condition is
forced by the user, the hardware will correct itself based on the result of the next stack
operation.
5.4.5.4
Reserved Stack Pointer Registration (Bits 6–23)
SP register bits 6 through 23 are reserved for future expansion and will read as zero dur-
ing read operations.
5.4.6 Loop Address Register
The LA is a read/write register which is stacked into the SSH by a DO instruction and is
unstacked by end-of-loop processing or by an ENDDO instruction. The contents of the LA
register indicate the location of the last instruction word in a program loop. When that last
instruction is fetched, the processor checks the contents of the LC register (see the fol-
lowing section). If the contents are not one, the processor decrements the LC and takes
the next instruction from the top of the SS. If the LC is one, the PC is incremented, the
loop flag is restored (pulled from the SS), the SS is purged, the LA and LC registers are
pulled from the SS and restored, and instruction execution continues normally.
5.4.7 Loop Counter Register
The LC register is a special 16-bit counter which specifies the number of times a hardware
program loop shall be repeated. This register is stacked into the SSL by a DO instruction
and unstacked by end-of-loop processing or by execution of an ENDDO instruction. When
the end of a hardware program loop is reached, the contents of the LC register are tested
for one. If the LC is one, the program loop is terminated, and the LC register is loaded with
the previous LC contents stored on the SS. If LC is not one, it is decremented and the
program loop is repeated. The LC can be read under program control, which allows the
number of times a loop will be executed to be monitored/changed dynamically. The LC is
also used in the REP instruction
5.4.8 Programming Model Summary
The complete programming model for the DSP56K central processing module is shown
in Figure 5-9. Programming models for the peripherals are shown in the appropriate user
manuals.
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 ...