Техническая Спецификация для Atmel SAM4S Xplained Pro Starter and Evaluation Kit ATSAM4S-XPRO ATSAM4S-XPRO
Модели
ATSAM4S-XPRO
177
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
12.6.9.2 SBFX and UBFX
Signed Bit Field Extract and Unsigned Bit Field Extract.
Syntax
Syntax
SBFX{cond} Rd, Rn, #lsb, #width
UBFX{cond} Rd, Rn, #lsb, #width
where:
condis an optional condition code, see
condis an optional condition code, see
.
Rdis the destination register.
Rnis the source register.
lsbis the position of the least significant bit of the bitfield. lsb must be in the range
Rnis the source register.
lsbis the position of the least significant bit of the bitfield. lsb must be in the range
0 to 31.
widthis the width of the bitfield and must be in the range 1 to 32-lsb.
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
widthis the width of the bitfield and must be in the range 1 to 32-lsb.
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
Restrictions
Do not use SP and do not use PC
.
Condition Flags
These instructions do not affect the flags.
Examples
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.