169
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
– MOV PC, Rm
–
B
,
BL
,
BX
,
BLX
– any
LDM
,
LDR
, or
POP
instruction that writes to the PC
–
TBB
and
TBH
• do not branch to any instruction inside an IT block, except when returning from an exception
handler
• all conditional instructions except
Bcond
must be inside an IT block.
Bcond
can be either outside
or inside an IT block but has a larger branch range if it is inside one
• each instruction inside the IT block must specify a condition code suffix that is either the
same or logical inverse as for the other instructions in the block.
Your assembler might place extra restrictions on the use of IT blocks, such as prohibiting the
use of assembler directives within them.
Condition Flags
This instruction does not change the flags.
Example
ITTE
NE
; Next 3 instructions are conditional
ANDNE
R0, R0, R1
; ANDNE does not update condition flags
ADDSNE R2, R2, #1
; ADDSNE updates condition flags
MOVEQ
R2, R3
; Conditional move
CMP
R0, #9
; Convert R0 hex value (0 to 15) into ASCII
; ('0'-'9', 'A'-'F')
ITE
GT
; Next 2 instructions are conditional
ADDGT
R1, R0, #55
; Convert 0xA -> 'A'
ADDLE
R1, R0, #48
; Convert 0x0 -> '0'
IT
GT
; IT block with only one conditional instruction
ADDGT
R1, R1, #1
; Increment R1 conditionally
ITTEE
EQ
; Next 4 instructions are conditional
MOVEQ
R0, R1
; Conditional move
ADDEQ
R2, R2, #10
; Conditional add
ANDNE
R3, R3, #1
; Conditional AND
BNE.W
dloop
; Branch instruction can only be used in the last
; instruction of an IT block
IT
NE
; Next instruction is conditional
ADD
R0, R0, R1
; Syntax error: no condition code used in IT block
Summary of Contents for SAM4S Series
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Page 1143: ...1143 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 4 64 lead LQFP Package Drawing ...
Page 1145: ...1145 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 5 64 lead QFN Package Drawing ...