发布时间 : 星期二 文章ARM汇编语言程序设计总结更新完毕开始阅读
ARM汇编语言程序设计总结
一、常用指令
1．存储器访问指令
LDR STR
LDR
Load 32-bit word to Memory. Syntax
LDR{cond} Rd, [Rn]
LDR{cond} Rd, [Rn, offset] LDR{cond} Rd, [Rn, offset]! LDR{cond} Rd, label LDR{cond} Rd, [Rn], offset Description
LDR{cond} Rd, [Rn, offset] (Pre-indexed offset) Rn and offset are added and used as address value.
LDR{cond} Rd, [Rn, offset]{!} (Pre-indexed offset with update)
Rn and offset are added and used as address value. The new address value is written to Rn. LDR{cond} Rd, label (Program-relative)
The assembler calculates the PC offset and generates LDR{cond} Rd, [R15, offset]. LDR{cond} Rd, [Rn], offset (Post-indexed offset)
Rn is used as address value. After memory transfer, the offset is added to Rn. Example
LDR{cond} Rd, [Rn] (zero offset)
Rn is used as address value.
LDR R8,[R10] //loads r8 from the address in r10. LDRNE R2,[R5,#960]! //(conditionally) loads r2 from a word 960 bytes above the address in r5, and increments r5 by 960.
LDR R0,localdata //loads a word located at label localdata
STR
Store register 32-bit words to Memory. The address must be 32-bit word-aligned.
Syntax STR{cond} Rd, [Rn]
STR{cond} Rd, [Rn, offset] STR{cond} Rd, [Rn, offset]! STR{cond} Rd, label
STR{cond} Rd, [Rn], offset Description
STR{cond} Rd, [Rn] (zero offset)
Rn is used as address value.
STR{cond} Rd, [Rn, offset] (Pre-indexed offset) Rn and offset are added and used as address value.
STR{cond} Rd, [Rn, offset]! (Pre-indexed offset with update)
Rn and offset are added and used as address value. The new address value is written to Rn. STR{cond} Rd, label (Program-relative)
The assembler calculates the PC offset and generates STR{cond} Rd, [R15], offset. STR{cond} Rd, [Rn], offset (Post-indexed offset)
Rn is used as address value. After memory transfer, the offset is added to Rn. Example
LDR r8,[r10] //loads r8 from the address in r10.
LDRNE r2,[r5,#960]! //(conditionally) loads r2 from a word //960 bytes above the address in r5, and //increments r5 by 960.
STR r2,[r9,#consta-struc] //consta-struc is an expression evaluating
//to a constant in the range 0-4095. STRB r0,[r3,-r8,ASR #2] //stores the least significant byte from
//r0 to a byte at an address equal to //contents(r3) minus contents(r9)/4. //r3 and r8 are not altered.
STR r5,[r7],#-8 //stores a word from r5 to the address //in r7, and then decrements r7 by 8. LDR r0,localdata //loads a word located at label localdata
2．一般数据处理指令
ADD SUB ADC SBC
AND, ORR, EOR, CMP TST
UMULL, UMLAL, SMULL, and SMLAL MUL, MLA, and MLS
ADC
Add with Carry. Syntax Description
ADC{cond}{S} Rd, Rn, Op2
Add Rn and Op2 and Carry flag and store result to Rd. ADC is typical used
for multi-word arithmetic.
Condition Flags If S is specified update flags: N, Z, C, V. Example
ADDS R0,R2,R4 // add R2 + R4, store result to R0, set flags
ADC R1,R3,R5 // add R3 + R5 with carry from previous ADDS, store result to R1
ADD
Add values and store result to register. Syntax Description Example
ADD{cond}{S} Rd, Rn, Op2
Add Rn and Op2 and store result to Rd.
Condition Flags If S is specified update flags: N, Z, C, V.
ADDS R0,R2,R4 //Add R2 and R4 and store result to R0, update flags
ADD R4,R4,#0xFF00 //Add value in 0xFF00 and R4 and store result in R4
SUB
Subtract registers. Syntax Description Condition Flags Example
SUB{cond}{S} Rd, Rn, Op2
subtracts the value of Op2 from the value in Rn. If S is specified update flags: N, Z, C, V.
SUBS R8,R6,#240 //R8=R6-240
SBC
Subtract with carry. Syntax Description Condition Flags Example
SBC{cond}{S} Rd, Rn, Op2 synthesize multiword arithmetic. If S is specified update flags: N, Z, C, V.
ADDS R0,R2,R4
ADD R4,R4,#0xFF00
AND
Logical AND operation. Syntax Description
AND{cond}{S} Rd, Rn, Op2
Load Rd with logical AND of Rn with Op2. Rd := Rn AND Op2
Condition Flags If S is specified, N, Z flags are updated. C flag may be updated by calculation of Op2. Example
AND R9,R2,#0xFF00 // Load R9 with R2 and value in 0xFF00
ORR
Logical OR operation. Syntax Description
ORR{cond}{S} Rd, Rn, Op2
OR operations on the values in Rn and Op2.
Condition Flags If S is specified, N, Z flags are updated. C flag may be updated by calculation of Op2. Example
ORR R2, R0, R5 // Rd = R0 or R5
CMP
Compare. Used in combination with conditional branch instructions. Syntax Description
CMP {cond} Rn, Op2
subtracts the value of Op2 from the value in Rn (equals to the SUBS
instruction with a discarded result).
This instruction updates the condition flags, but do not place a result in a register. Condition Flags N, Z, C and V flags are updated. Example
CMP R2, R9 //Subtract value of R9 from R2
TST
Test.