arm.txt

arm指令伪代码 arm指令伪代码

数据处理指令操作数的具体寻址方式
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#<immdediate>
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shifter_operand = immed_8 Rotate_Right (rotate_imm*2)
if Rotate_imm == 0 then
	shifter_carry_out = C falg
else /* rotate_imm != 0 */
	shifter_carry_out =shifter_operand[31]

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<Rm>
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shifter_operand = Rm
shifter_carry_out = C flag

当R15(PC)用作第1个源操作数Rn或者第2个源操作数Rm时,操作数即为当前指令地址加常数8

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<Rm>,LSL #<shift_imm>
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if shift_imm == 0 then
	shifter_operand = Rm
	shifter_carry_out = C flag
else /* shift_imm>0 */
	shifter_operand = Rm Logical_Shift_Left shift_imm
	shifter_carry_out = Rm[32-shift_imm]

当R15(PC)用作第1个源操作数Rn或者第2个源操作数Rm时,操作数即为当前指令地址加常数8

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<Rm>,LSL <Rs>
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if Rs[7:0] == 0
	shifter_operand = Rm
	shifter_carry_out= C flag
else if Rs[7:0] < 32
	shifter_operand = Rm Logical_Shift_Left Rs[7:0]
	shifter_carry_out=Rm[32-Rs[7:0]]
else if Rs[7:0]==32
	shifter_operand = 0
	shifter_carry_out=Rm[0]
else Rs[7:0]>32
	shifter_operand = 0
	shifter_carry_out=0

当R15(PC)用作Rn、Rm、Rd及Rs时，会产生不可预知的结果

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