ADSP-2104/ADSP-2109

REV. 0

–11–

Program Flow Instructions

DO <addr> [UNTIL term] ;

Do Until Loop

[IF cond] JUMP (Ix) ;

Jump

[IF cond] JUMP <addr>;

[IF cond] CALL (Ix) ;

Call Subroutine

[IF cond] CALL <addr>;

IF [NOT ] FLAG_IN

JUMP <addr>;

Jump/Call on Flag In Pin

IF [NOT ] FLAG_IN

CALL <addr>;

[IF cond] SET|RESET|TOGGLE

FLAG_OUT [, ...] ;

Modify Flag Out Pin

[IF cond] RTS ;

Return from Subroutine

[IF cond] RTI ;

Return from Interrupt Service Routine

IDLE [(n)] ;

Idle

Miscellaneous Instructions

NOP ;

No Operation

MODIFY (Ix , My);

Modify Address Register

[PUSH STS] [, POP CNTR] [, POP PC] [, POP LOOP] ;

Stack Control

ENA|DIS

SEC_REG [, ...] ;

Mode Control

BIT_REV

AV_LATCH

AR_SAT

M_MODE

TIMER

G_MODE

Notation Conventions

Ix

Index registers for indirect addressing

My

Modify registers for indirect addressing

<data>

Immediate data value

<addr>

Immediate address value

<exp>

Exponent (shift value) in shift immediate instructions (8-bit signed number)

<ALU>

Any ALU instruction (except divide)

<MAC>

Any multiply-accumulate instruction

<SHIFT>

Any shift instruction (except shift immediate)

cond

Condition code for conditional instruction

term

Termination code for DO UNTIL loop

dreg

Data register (of ALU, MAC, or Shifter)

reg

Any register (including dregs)

;

A semicolon terminates the instruction

,

Commas separate multiple operations of a single instruction

[

]

Optional part of instruction

[, ...]

Optional, multiple operations of an instruction

option1 | option2

List of options; choose one.

Assembly Code Example

The following example is a code fragment that performs the filter tap update for an adaptive filter based on a least-mean-squared

algorithm. Notice that the computations in the instructions are written like algebraic equations.

MF=MX0* M Y1 ( RND), MX0=DM(I2,M1);

{ M F=error * beta}

MR=MX0* M F ( RND), AY0=PM(I6,M5);

DO adapt UNTIL CE;

AR=MR1+AY0, MX0=DM(I2,M1), AY0=PM(I6,M7);

adapt:

PM(I6,M6)= A R, MR=MX0* MF ( RND);

MODIFY(I2,M3);

{Point to oldest data}

MODIFY(I6,M7);

{Point to start of data}