ARM base instruction -- ccmp
Conditional Compare (register) sets the value of the condition flags to the result of the comparison of two registers if the condition is TRUE, and an immediate value otherwise.
条件比较(寄存器)如果条件为真,则将条件标志的值设置为两个寄存器的比较结果,否则设置为立即值。
32-bit variant:
CCMP <Wn>, <Wm>, #<nzcv>, <cond>
64-bit variant:
CCMP <Xn>, <Xm>, #<nzcv>, <cond>
ccmp x13, x12, #0x0, ne # 双重比较. 判断 x13 和 x12 同时存在,即都不等于0。将ne设置到标志寄存器。
4037b8: 1100079c add w28, w28, #0x1 // this->argc+1
4037bc: b900527c str w28, [x19, #80] // this->argc++;
4037c0: 3864cb20 ldrb w0, [x25, w4, sxtw] // w0=0=args[i] cpsr=0x80201000 [ EL=0 SSBS SS N ]
4037c4: 7100001f cmp w0, #0x0 // cpsr=0x60201000 [ EL=0 SSBS SS C Z ]
4037c8: 7a440064 ccmp w3, w4, #0x4, eq // eq = none, w3=0xb=size-1, w4=4=i cpsr=0x20201000 [ EL=0 SSBS SS C ]
4037cc: 54fffecd b.le 4037a4 <ferror@plt+0x18c4>
#<nzcv>:
原文地址:https://blog.csdn.net/xiaozhiwise/article/details/142626107
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