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Bit 22 in some LD/ST instructions (Cortex-A7)

Juha Aaltonen

I wonder if the bit 22 has some function in instructions like LDRH, STRH, LDRSBT, LDRD, ... (bits 27, 26, 25 = 0, 0, 0)?

                           22
c c c c 0 0 0  0  U 1  1  0 n n n n t t t t x x x x 1 0 1 1 x x x x STRHT<c> <Rt>,[<Rn>],{,#+/-<imm8>}  A1  A8.8.219
c c c c 0 0 0  0  U 1  1  1 n n n n t t t t x x x x 1 0 1 1 x x x x LDRHT<c> <Rt>,[<Rn>],{,#+/-<imm8>}  A1  A8.8.83
c c c c 0 0 0  0  U 1  1  1 n n n n t t t t x x x x 1 1 0 1 x x x x LDRSBT<c> <Rt>,[<Rn>],{,#+/-<imm8>}  A1  A8.8.87
c c c c 0 0 0 (1) U 1 (0) 0 1 1 1 1 t t t t x x x x 1 1 0 1 x x x xLDRD<c> <Rt>,<Rt2>,<label> LDRD<c> <Rt>,<Rt2>,[PC,#-0]  A1  A8.8.73
c c c c 0 0 0  P  U 0  W  0 n n n n t t t t (0) (0) (0) (0) 1 1 0 1 m m m m> LDRD<c> <Rt>,<Rt2>,[<Rn>,+/-<Rm>]{!} LDRD<c> <Rt>,<Rt2>,[<Rn>],+/-<Rm>  A1  A8.8.74

In some instructions, like LDR, STR, LDRB (bits 27, 26, 25 = 0, 1, 1) , I understand, it chooses between byte and word access.

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