Freescale Semiconductor SC140 specifications Jfd, JFD label, JFD Rn

Models: SC140

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JFD

JFD

Jump If False Using a Delay Slot (AGU)

Operation

 

Assembler Syntax

If T==0, then label → PC

JFD label [0 ≤ label < 232,W]

If T==0, then Rn → PC

JFD Rn

JFD

Description

If the T bit is cleared, program execution continues at a specified 32-bit memory destination address after executing the execution set in the delay slot. If the T bit is set, the PC is updated to point to the next execution set and program execution continues sequentially. The destination address cannot be in the middle of an execution set.

JFD label

Jumps to the absolute memory address specified by a label after executing the set in the delay slot. The assembler and linker calculate the destination address from the label.

JFD Rn

Jumps to the memory address specified in an address register (Rn) after executing the execution set in the delay slot.

Status and Conditions that Affect Instruction

Register Address

Bit Name

Description

SR[1]

T

True bit

Status and Conditions changed by Instruction

None.

Example

JFD R0

Instruction

Result

cmpeq.w #$35,d1

Not equal, so T bit in SR cleared.

move.w #adr,r0

Places the numerical address of adr in r0.

nop

 

Delay needed after write to pointer.

jfd

r0 move.w #$29,d1

Jump to adr, move.w executed.

inc

d1

Increment d1 to $2A.

move.w #$47,d2

Skipped over.

- - - -

Skipped over.

- - - -

Skipped over.

- - - -

Skipped over.

adr move.w #$1A,d4

Execution continues here at lbl.

SC140 DSP Core Reference Manual

A-207

Page 521
Image 521
Freescale Semiconductor SC140 specifications Jfd, JFD label, JFD Rn