// SPDX-License-Identifier: GPL-2.0 /* * arch/sh/kernel/cpu/sh2a/opcode_helper.c * * Helper for the SH-2A 32-bit opcodes. * * Copyright (C) 2007 Paul Mundt */ #include <linux/kernel.h> /* * Instructions on SH are generally fixed at 16-bits, however, SH-2A * introduces some 32-bit instructions. Since there are no real * constraints on their use (and they can be mixed and matched), we need * to check the instruction encoding to work out if it's a true 32-bit * instruction or not. * * Presently, 32-bit opcodes have only slight variations in what the * actual encoding looks like in the first-half of the instruction, which * makes it fairly straightforward to differentiate from the 16-bit ones. * * First 16-bits of encoding Used by * * 0011nnnnmmmm0001 mov.b, mov.w, mov.l, fmov.d, * fmov.s, movu.b, movu.w * * 0011nnnn0iii1001 bclr.b, bld.b, bset.b, bst.b, band.b, * bandnot.b, bldnot.b, bor.b, bornot.b, * bxor.b * * 0000nnnniiii0000 movi20 * 0000nnnniiii0001 movi20s */ unsigned int instruction_size(unsigned int insn) { /* Look for the common cases */ switch ((insn & 0xf00f)) { case 0x0000: /* movi20 */ case 0x0001: /* movi20s */ case 0x3001: /* 32-bit mov/fmov/movu variants */ return 4; } /* And the special cases.. */ switch ((insn & 0xf08f)) { case 0x3009: /* 32-bit b*.b bit operations */ return 4; } return 2; }