ARM指令集：
其中包括数据处理指令集
1）算术指令（ADD,ADC,SUB,SBC , RSB, RSC ）
①加法指令：ADD，ADDS
其中带S的表示可以更新标志位
ADD/ADDS
Add values and store result to register.
| Syntax | ADD{cond}{S} Rd, Rn, Op2 | |
| Description | Add Rn and Op2 and store result to Rd. | |
| Condition Flags | If S is specified update flags: N, Z, C, V. | |
| Example |
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
|
Add with Carry.
| Syntax | ADC{cond}{S} Rd, Rn, Op2 | |
| Description | 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 |
原文：http://blog.csdn.net/cj_kano/article/details/41827671