Atmel SAM4S Series, Preliminary Data Sheet

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163
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
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.
11.6.9.2 SBFX and UBFX
Signed Bit Field Extract and Unsigned Bit Field Extract.
Syntax
SBFX{cond} Rd, Rn, #lsb, #width
UBFX{cond} Rd, Rn, #lsb, #width
where:
Operation
SBFX
extracts a bitfield from one register, sign extends it to 32 bits, and writes the result to the
destination register.
UBFX
extracts a bitfield from one register, zero extends it to 32 bits, and writes the result to the
destination register.
Restrictions
Do not use SP and do not use PC
.
Condition Flags
These instructions do not affect the flags.
Examples
SBFX R0, R1, #20, #4 ; Extract bit 20 to bit 23 (4 bits) from R1 and sign
; extend to 32 bits and then write the result to R0.
UBFX R8, R11, #9, #10 ; Extract bit 9 to bit 18 (10 bits) from R11 and
; zero, extend to 32 bits and then write the result
; to R8.
cond is an optional condition code, see “Conditional Execution” .
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 .