= Thumb 16-bit instruction set quick reference by Arm
{c}
https://documentation-service.arm.com/static/5ed67dc7ca06a95ce53f9334
Page 1 lists the compact logical and shift instruction forms. <Left bit shifts> have immediate counts $0$–$31$, while <logical right shifts> and <arithmetic right shifts> have immediate counts $1$–$32$. The logical <bitwise AND> entry uses a <processor register> operand. These encoding details explain why extracting low <bits> with two immediate shifts can avoid materializing a <bit mask>.
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