ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Instruction Details
A8.6.17 BFC
Bit Field Clear clears any number of adjacent bits at any position in a register, without affecting the other
bits in the register.
Encoding T1 ARMv6T2, ARMv7
BFC ,#,#
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 1 0 (0) 1 1 0 1 1 0 1 1 1 1 0 imm3 Rd imm2 (0) msb
d = UInt(Rd); msbit = UInt(msb); lsbit = UInt(imm3:imm2);
if BadReg(d) then UNPREDICTABLE;
Encoding A1 ARMv6T2, ARMv7
BFC ,#,#
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
cond 0 1 1 1 1 1 0 msb Rd lsb 0 0 1 1 1 1 1
d = UInt(Rd); msbit = UInt(msb); lsbit = UInt(lsb);
if d == 15 then UNPREDICTABLE;
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