Atmel SAM4S-XPLD Atmel ATSAM4S-XPLD ATSAM4S-XPLD Hoja De Datos

 167

SAM4S [DATASHEET]

11100E–ATARM–24-Jul-13

Restrictions

The restrictions are:



Rn must not be SP



Rm must not be SP and must not be PC



When any of these instructions is used inside an IT block, it must be the last instruction of the IT block.

Condition Flags

These instructions do not change the flags.

Examples

    ADR.W  R0, BranchTable_Byte

    TBB    [R0, R1]     ; R1 is the index, R0 is the base address of the

                        ; branch table

Case1

; an instruction sequence follows

Case2

; an instruction sequence follows

Case3

; an instruction sequence follows

BranchTable_Byte

    DCB    0                  ; Case1 offset calculation

    DCB    ((Case2-Case1)/2)  ; Case2 offset calculation

    DCB    ((Case3-Case1)/2)  ; Case3 offset calculation

    TBH    [PC, R1, LSL #1]   ; R1 is the index, PC is used as base of the

                              ; branch table

BranchTable_H

    DCI    ((CaseA - BranchTable_H)/2)  ; CaseA offset calculation

    DCI    ((CaseB - BranchTable_H)/2)  ; CaseB offset calculation

    DCI    ((CaseC - BranchTable_H)/2)  ; CaseC offset calculation

CaseA

; an instruction sequence follows

CaseB

; an instruction sequence follows

CaseC

; an instruction sequence follows