ARM BLX does not set Registers modified

[McLovi9]

test@test ~ $ cstool -d arm B60100FA
0  b60100fa  blx	#0x6e0
	op_count: 1
		operands[0].type: IMM = 0x6e0
	Registers read: pc
	Registers modified: lr
	Groups: call branch_relative arm v5t jump 

pc register should be also included in Registers modified

[aquynh]

on "next" branch, you have:

cstool -d arm B60100FA                   
0  b60100fa  blx	#0x6e0
	op_count: 1
		operands[0].type: IMM = 0x6e0
	Registers read: pc
	Registers modified: lr
	Groups: call branch_relative arm v5t jump 

so you can verify if instruction belongs to JUMP or CALL groups instead

[10110111]

In fact one could say that all the instructions modify PC — most just set it to address after the instruction. Capstone seems quite consistent on this — on x86 too the jumps and calls aren't reported to modify rIP.

[McLovi9]

@10110111 :

Capstone seems quite consistent on this

the issue is that capstone is NOT consistent on this. Look at BL instruction

test@test ~ $ cstool -d arm  8A1B00EB  
0  8a1b00eb  bl	#0x6e30
	op_count: 1
		operands[0].type: IMM = 0x6e30
	Registers read: pc
	Registers modified: lr pc
	Groups: call branch_relative arm jump 

Registers modified: lr pc