164
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
11.6.9.3
SXT and UXT
Sign extend and Zero extend.
Syntax
SXTextend{cond} {Rd,} Rm {, ROR #n}
UXTextend{cond} {Rd}, Rm {, ROR #n}
where:
Operation
These instructions do the following:
1.
Rotate the value from
Rm
right by 0, 8, 16 or 24 bits.
2.
Extract bits from the resulting value:
–
SXTB
extracts bits[7:0] and sign extends to 32 bits.
–
UXTB
extracts bits[7:0] and zero extends to 32 bits.
–
SXTH
extracts bits[15:0] and sign extends to 32 bits.
–
UXTH
extracts bits[15:0] and zero extends to 32 bits.
Restrictions
Do not use SP and do not use PC.
Condition Flags
These instructions do not affect the flags.
Examples
SXTH
R4, R6, ROR #16
; Rotate R6 right by 16 bits, then obtain the lower
; halfword of the result and then sign extend to
; 32 bits and write the result to R4.
UXTB
R3, R10
; Extract lowest byte of the value in R10 and zero
; extend it, and write the result to R3.
extend
is one of:
B
Extends an 8-bit value to a 32-bit value.
H
Extends a 16-bit value to a 32-bit value.
cond
is an optional condition code, see
Rd
is the destination register.
Rm
is the register holding the value to extend.
ROR #n
is one of:
ROR #8
Value from
Rm
is rotated right 8 bits.
ROR #16
Value from
Rm
is rotated right 16 bits.
ROR #24
Value from
Rm
is rotated right 24 bits.
.
If
ROR #n
is omitted, no rotation is performed
Содержание SAM4S Series
Страница 44: ...44 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Страница 412: ...412 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Страница 1105: ...1105 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Страница 1142: ...1142 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 3 100 ball VFBGA Package Drawing ...
Страница 1143: ...1143 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 4 64 lead LQFP Package Drawing ...
Страница 1145: ...1145 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 5 64 lead QFN Package Drawing ...