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SAM4S [DATASHEET]

11100E–ATARM–24-Jul-13

Bit Field Clear and Bit Field Insert.

Syntax

BFC{cond} Rd, #lsb, #width

BFI{cond} Rd, Rn, #lsb, #width

where:

cond

Rd

is the destination register.

Rn

is the source register.

lsb

is the position of the least significant bit of the bitfield. lsb must be in the range
0 to 31.

width

is the width of the bitfield and must be in the range 1 to 32-lsb.

Operation

BFC clears a bitfield in a register. It clears width bits in Rd, starting at the low bit position lsb. Other bits in Rd are
unchanged.

BFI copies a bitfield into one register from another register. It replaces width bits in Rd starting at the low bit position lsb,
with width bits from Rn starting at bit[0]. Other bits in Rd are unchanged.

Restrictions

Do not use SP and do not use PC.

Condition Flags

These instructions do not affect the flags.

Examples

    BFC   R4, #8, #12       ; Clear bit 8 to bit 19 (12 bits) of R4 to 0

    BFI   R9, R2, #8, #12   ; Replace bit 8 to bit 19 (12 bits) of R9 with

                            ; bit 0 to bit 11 from R2.