/* * Unaligned memory access handler * * Copyright (C) 2001 Randolph Chung <tausq@debian.org> * Significantly tweaked by LaMont Jones <lamont@debian.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ #include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/signal.h> #include <asm/uaccess.h> /* #define DEBUG_UNALIGNED 1 */ #ifdef DEBUG_UNALIGNED #define DPRINTF(fmt, args...) do { printk(KERN_DEBUG "%s:%d:%s ", __FILE__, __LINE__, __FUNCTION__ ); printk(KERN_DEBUG fmt, ##args ); } while (0) #else #define DPRINTF(fmt, args...) #endif #ifdef CONFIG_64BIT #define RFMT "%016lx" #else #define RFMT "%08lx" #endif #define FIXUP_BRANCH(lbl) \ "\tldil L%%" #lbl ", %%r1\n" \ "\tldo R%%" #lbl "(%%r1), %%r1\n" \ "\tbv,n %%r0(%%r1)\n" /* If you use FIXUP_BRANCH, then you must list this clobber */ #define FIXUP_BRANCH_CLOBBER "r1" /* 1111 1100 0000 0000 0001 0011 1100 0000 */ #define OPCODE1(a,b,c) ((a)<<26|(b)<<12|(c)<<6) #define OPCODE2(a,b) ((a)<<26|(b)<<1) #define OPCODE3(a,b) ((a)<<26|(b)<<2) #define OPCODE4(a) ((a)<<26) #define OPCODE1_MASK OPCODE1(0x3f,1,0xf) #define OPCODE2_MASK OPCODE2(0x3f,1) #define OPCODE3_MASK OPCODE3(0x3f,1) #define OPCODE4_MASK OPCODE4(0x3f) /* skip LDB - never unaligned (index) */ #define OPCODE_LDH_I OPCODE1(0x03,0,0x1) #define OPCODE_LDW_I OPCODE1(0x03,0,0x2) #define OPCODE_LDD_I OPCODE1(0x03,0,0x3) #define OPCODE_LDDA_I OPCODE1(0x03,0,0x4) #define OPCODE_LDCD_I OPCODE1(0x03,0,0x5) #define OPCODE_LDWA_I OPCODE1(0x03,0,0x6) #define OPCODE_LDCW_I OPCODE1(0x03,0,0x7) /* skip LDB - never unaligned (short) */ #define OPCODE_LDH_S OPCODE1(0x03,1,0x1) #define OPCODE_LDW_S OPCODE1(0x03,1,0x2) #define OPCODE_LDD_S OPCODE1(0x03,1,0x3) #define OPCODE_LDDA_S OPCODE1(0x03,1,0x4) #define OPCODE_LDCD_S OPCODE1(0x03,1,0x5) #define OPCODE_LDWA_S OPCODE1(0x03,1,0x6) #define OPCODE_LDCW_S OPCODE1(0x03,1,0x7) /* skip STB - never unaligned */ #define OPCODE_STH OPCODE1(0x03,1,0x9) #define OPCODE_STW OPCODE1(0x03,1,0xa) #define OPCODE_STD OPCODE1(0x03,1,0xb) /* skip STBY - never unaligned */ /* skip STDBY - never unaligned */ #define OPCODE_STWA OPCODE1(0x03,1,0xe) #define OPCODE_STDA OPCODE1(0x03,1,0xf) #define OPCODE_FLDWX OPCODE1(0x09,0,0x0) #define OPCODE_FLDWXR OPCODE1(0x09,0,0x1) #define OPCODE_FSTWX OPCODE1(0x09,0,0x8) #define OPCODE_FSTWXR OPCODE1(0x09,0,0x9) #define OPCODE_FLDWS OPCODE1(0x09,1,0x0) #define OPCODE_FLDWSR OPCODE1(0x09,1,0x1) #define OPCODE_FSTWS OPCODE1(0x09,1,0x8) #define OPCODE_FSTWSR OPCODE1(0x09,1,0x9) #define OPCODE_FLDDX OPCODE1(0x0b,0,0x0) #define OPCODE_FSTDX OPCODE1(0x0b,0,0x8) #define OPCODE_FLDDS OPCODE1(0x0b,1,0x0) #define OPCODE_FSTDS OPCODE1(0x0b,1,0x8) #define OPCODE_LDD_L OPCODE2(0x14,0) #define OPCODE_FLDD_L OPCODE2(0x14,1) #define OPCODE_STD_L OPCODE2(0x1c,0) #define OPCODE_FSTD_L OPCODE2(0x1c,1) #define OPCODE_LDW_M OPCODE3(0x17,1) #define OPCODE_FLDW_L OPCODE3(0x17,0) #define OPCODE_FSTW_L OPCODE3(0x1f,0) #define OPCODE_STW_M OPCODE3(0x1f,1) #define OPCODE_LDH_L OPCODE4(0x11) #define OPCODE_LDW_L OPCODE4(0x12) #define OPCODE_LDWM OPCODE4(0x13) #define OPCODE_STH_L OPCODE4(0x19) #define OPCODE_STW_L OPCODE4(0x1A) #define OPCODE_STWM OPCODE4(0x1B) #define MAJOR_OP(i) (((i)>>26)&0x3f) #define R1(i) (((i)>>21)&0x1f) #define R2(i) (((i)>>16)&0x1f) #define R3(i) ((i)&0x1f) #define FR3(i) ((((i)<<1)&0x1f)|(((i)>>6)&1)) #define IM(i,n) (((i)>>1&((1<<(n-1))-1))|((i)&1?((0-1L)<<(n-1)):0)) #define IM5_2(i) IM((i)>>16,5) #define IM5_3(i) IM((i),5) #define IM14(i) IM((i),14) #define ERR_NOTHANDLED -1 #define ERR_PAGEFAULT -2 int unaligned_enabled __read_mostly = 1; void die_if_kernel (char *str, struct pt_regs *regs, long err); static int emulate_ldh(struct pt_regs *regs, int toreg) { unsigned long saddr = regs->ior; unsigned long val = 0; int ret; DPRINTF("load " RFMT ":" RFMT " to r%d for 2 bytes\n", regs->isr, regs->ior, toreg); __asm__ __volatile__ ( " mtsp %4, %%sr1\n" "1: ldbs 0(%%sr1,%3), %%r20\n" "2: ldbs 1(%%sr1,%3), %0\n" " depw %%r20, 23, 24, %0\n" " copy %%r0, %1\n" "3: \n" " .section .fixup,\"ax\"\n" "4: ldi -2, %1\n" FIXUP_BRANCH(3b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b, 4b) ASM_EXCEPTIONTABLE_ENTRY(2b, 4b) : "=r" (val), "=r" (ret) : "0" (val), "r" (saddr), "r" (regs->isr) : "r20", FIXUP_BRANCH_CLOBBER ); DPRINTF("val = 0x" RFMT "\n", val); if (toreg) regs->gr[toreg] = val; return ret; } static int emulate_ldw(struct pt_regs *regs, int toreg, int flop) { unsigned long saddr = regs->ior; unsigned long val = 0; int ret; DPRINTF("load " RFMT ":" RFMT " to r%d for 4 bytes\n", regs->isr, regs->ior, toreg); __asm__ __volatile__ ( " zdep %3,28,2,%%r19\n" /* r19=(ofs&3)*8 */ " mtsp %4, %%sr1\n" " depw %%r0,31,2,%3\n" "1: ldw 0(%%sr1,%3),%0\n" "2: ldw 4(%%sr1,%3),%%r20\n" " subi 32,%%r19,%%r19\n" " mtctl %%r19,11\n" " vshd %0,%%r20,%0\n" " copy %%r0, %1\n" "3: \n" " .section .fixup,\"ax\"\n" "4: ldi -2, %1\n" FIXUP_BRANCH(3b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b, 4b) ASM_EXCEPTIONTABLE_ENTRY(2b, 4b) : "=r" (val), "=r" (ret) : "0" (val), "r" (saddr), "r" (regs->isr) : "r19", "r20", FIXUP_BRANCH_CLOBBER ); DPRINTF("val = 0x" RFMT "\n", val); if (flop) ((__u32*)(regs->fr))[toreg] = val; else if (toreg) regs->gr[toreg] = val; return ret; } static int emulate_ldd(struct pt_regs *regs, int toreg, int flop) { unsigned long saddr = regs->ior; __u64 val = 0; int ret; DPRINTF("load " RFMT ":" RFMT " to r%d for 8 bytes\n", regs->isr, regs->ior, toreg); #ifdef CONFIG_PA20 #ifndef CONFIG_64BIT if (!flop) return -1; #endif __asm__ __volatile__ ( " depd,z %3,60,3,%%r19\n" /* r19=(ofs&7)*8 */ " mtsp %4, %%sr1\n" " depd %%r0,63,3,%3\n" "1: ldd 0(%%sr1,%3),%0\n" "2: ldd 8(%%sr1,%3),%%r20\n" " subi 64,%%r19,%%r19\n" " mtsar %%r19\n" " shrpd %0,%%r20,%%sar,%0\n" " copy %%r0, %1\n" "3: \n" " .section .fixup,\"ax\"\n" "4: ldi -2, %1\n" FIXUP_BRANCH(3b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b,4b) ASM_EXCEPTIONTABLE_ENTRY(2b,4b) : "=r" (val), "=r" (ret) : "0" (val), "r" (saddr), "r" (regs->isr) : "r19", "r20", FIXUP_BRANCH_CLOBBER ); #else { unsigned long valh=0,vall=0; __asm__ __volatile__ ( " zdep %5,29,2,%%r19\n" /* r19=(ofs&3)*8 */ " mtsp %6, %%sr1\n" " dep %%r0,31,2,%5\n" "1: ldw 0(%%sr1,%5),%0\n" "2: ldw 4(%%sr1,%5),%1\n" "3: ldw 8(%%sr1,%5),%%r20\n" " subi 32,%%r19,%%r19\n" " mtsar %%r19\n" " vshd %0,%1,%0\n" " vshd %1,%%r20,%1\n" " copy %%r0, %2\n" "4: \n" " .section .fixup,\"ax\"\n" "5: ldi -2, %2\n" FIXUP_BRANCH(4b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b,5b) ASM_EXCEPTIONTABLE_ENTRY(2b,5b) ASM_EXCEPTIONTABLE_ENTRY(3b,5b) : "=r" (valh), "=r" (vall), "=r" (ret) : "0" (valh), "1" (vall), "r" (saddr), "r" (regs->isr) : "r19", "r20", FIXUP_BRANCH_CLOBBER ); val=((__u64)valh<<32)|(__u64)vall; } #endif DPRINTF("val = 0x%llx\n", val); if (flop) regs->fr[toreg] = val; else if (toreg) regs->gr[toreg] = val; return ret; } static int emulate_sth(struct pt_regs *regs, int frreg) { unsigned long val = regs->gr[frreg]; int ret; if (!frreg) val = 0; DPRINTF("store r%d (0x" RFMT ") to " RFMT ":" RFMT " for 2 bytes\n", frreg, val, regs->isr, regs->ior); __asm__ __volatile__ ( " mtsp %3, %%sr1\n" " extrw,u %1, 23, 8, %%r19\n" "1: stb %1, 1(%%sr1, %2)\n" "2: stb %%r19, 0(%%sr1, %2)\n" " copy %%r0, %0\n" "3: \n" " .section .fixup,\"ax\"\n" "4: ldi -2, %0\n" FIXUP_BRANCH(3b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b,4b) ASM_EXCEPTIONTABLE_ENTRY(2b,4b) : "=r" (ret) : "r" (val), "r" (regs->ior), "r" (regs->isr) : "r19", FIXUP_BRANCH_CLOBBER ); return ret; } static int emulate_stw(struct pt_regs *regs, int frreg, int flop) { unsigned long val; int ret; if (flop) val = ((__u32*)(regs->fr))[frreg]; else if (frreg) val = regs->gr[frreg]; else val = 0; DPRINTF("store r%d (0x" RFMT ") to " RFMT ":" RFMT " for 4 bytes\n", frreg, val, regs->isr, regs->ior); __asm__ __volatile__ ( " mtsp %3, %%sr1\n" " zdep %2, 28, 2, %%r19\n" " dep %%r0, 31, 2, %2\n" " mtsar %%r19\n" " depwi,z -2, %%sar, 32, %%r19\n" "1: ldw 0(%%sr1,%2),%%r20\n" "2: ldw 4(%%sr1,%2),%%r21\n" " vshd %%r0, %1, %%r22\n" " vshd %1, %%r0, %%r1\n" " and %%r20, %%r19, %%r20\n" " andcm %%r21, %%r19, %%r21\n" " or %%r22, %%r20, %%r20\n" " or %%r1, %%r21, %%r21\n" " stw %%r20,0(%%sr1,%2)\n" " stw %%r21,4(%%sr1,%2)\n" " copy %%r0, %0\n" "3: \n" " .section .fixup,\"ax\"\n" "4: ldi -2, %0\n" FIXUP_BRANCH(3b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b,4b) ASM_EXCEPTIONTABLE_ENTRY(2b,4b) : "=r" (ret) : "r" (val), "r" (regs->ior), "r" (regs->isr) : "r19", "r20", "r21", "r22", "r1", FIXUP_BRANCH_CLOBBER ); return 0; } static int emulate_std(struct pt_regs *regs, int frreg, int flop) { __u64 val; int ret; if (flop) val = regs->fr[frreg]; else if (frreg) val = regs->gr[frreg]; else val = 0; DPRINTF("store r%d (0x%016llx) to " RFMT ":" RFMT " for 8 bytes\n", frreg, val, regs->isr, regs->ior); #ifdef CONFIG_PA20 #ifndef CONFIG_64BIT if (!flop) return -1; #endif __asm__ __volatile__ ( " mtsp %3, %%sr1\n" " depd,z %2, 60, 3, %%r19\n" " depd %%r0, 63, 3, %2\n" " mtsar %%r19\n" " depdi,z -2, %%sar, 64, %%r19\n" "1: ldd 0(%%sr1,%2),%%r20\n" "2: ldd 8(%%sr1,%2),%%r21\n" " shrpd %%r0, %1, %%sar, %%r22\n" " shrpd %1, %%r0, %%sar, %%r1\n" " and %%r20, %%r19, %%r20\n" " andcm %%r21, %%r19, %%r21\n" " or %%r22, %%r20, %%r20\n" " or %%r1, %%r21, %%r21\n" "3: std %%r20,0(%%sr1,%2)\n" "4: std %%r21,8(%%sr1,%2)\n" " copy %%r0, %0\n" "5: \n" " .section .fixup,\"ax\"\n" "6: ldi -2, %0\n" FIXUP_BRANCH(5b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b,6b) ASM_EXCEPTIONTABLE_ENTRY(2b,6b) ASM_EXCEPTIONTABLE_ENTRY(3b,6b) ASM_EXCEPTIONTABLE_ENTRY(4b,6b) : "=r" (ret) : "r" (val), "r" (regs->ior), "r" (regs->isr) : "r19", "r20", "r21", "r22", "r1", FIXUP_BRANCH_CLOBBER ); #else { unsigned long valh=(val>>32),vall=(val&0xffffffffl); __asm__ __volatile__ ( " mtsp %4, %%sr1\n" " zdep %2, 29, 2, %%r19\n" " dep %%r0, 31, 2, %2\n" " mtsar %%r19\n" " zvdepi -2, 32, %%r19\n" "1: ldw 0(%%sr1,%3),%%r20\n" "2: ldw 8(%%sr1,%3),%%r21\n" " vshd %1, %2, %%r1\n" " vshd %%r0, %1, %1\n" " vshd %2, %%r0, %2\n" " and %%r20, %%r19, %%r20\n" " andcm %%r21, %%r19, %%r21\n" " or %1, %%r20, %1\n" " or %2, %%r21, %2\n" "3: stw %1,0(%%sr1,%1)\n" "4: stw %%r1,4(%%sr1,%3)\n" "5: stw %2,8(%%sr1,%3)\n" " copy %%r0, %0\n" "6: \n" " .section .fixup,\"ax\"\n" "7: ldi -2, %0\n" FIXUP_BRANCH(6b) " .previous\n" ASM_EXCEPTIONTABLE_ENTRY(1b,7b) ASM_EXCEPTIONTABLE_ENTRY(2b,7b) ASM_EXCEPTIONTABLE_ENTRY(3b,7b) ASM_EXCEPTIONTABLE_ENTRY(4b,7b) ASM_EXCEPTIONTABLE_ENTRY(5b,7b) : "=r" (ret) : "r" (valh), "r" (vall), "r" (regs->ior), "r" (regs->isr) : "r19", "r20", "r21", "r1", FIXUP_BRANCH_CLOBBER ); } #endif return ret; } void handle_unaligned(struct pt_regs *regs) { static unsigned long unaligned_count = 0; static unsigned long last_time = 0; unsigned long newbase = R1(regs->iir)?regs->gr[R1(regs->iir)]:0; int modify = 0; int ret = ERR_NOTHANDLED; struct siginfo si; register int flop=0; /* true if this is a flop */ /* log a message with pacing */ if (user_mode(regs)) { if (current->thread.flags & PARISC_UAC_SIGBUS) { goto force_sigbus; } if (unaligned_count > 5 && jiffies - last_time > 5*HZ) { unaligned_count = 0; last_time = jiffies; } if (!(current->thread.flags & PARISC_UAC_NOPRINT) && ++unaligned_count < 5) { char buf[256]; sprintf(buf, "%s(%d): unaligned access to 0x" RFMT " at ip=0x" RFMT "\n", current->comm, task_pid_nr(current), regs->ior, regs->iaoq[0]); printk(KERN_WARNING "%s", buf); #ifdef DEBUG_UNALIGNED show_regs(regs); #endif } if (!unaligned_enabled) goto force_sigbus; } /* handle modification - OK, it's ugly, see the instruction manual */ switch (MAJOR_OP(regs->iir)) { case 0x03: case 0x09: case 0x0b: if (regs->iir&0x20) { modify = 1; if (regs->iir&0x1000) /* short loads */ if (regs->iir&0x200) newbase += IM5_3(regs->iir); else newbase += IM5_2(regs->iir); else if (regs->iir&0x2000) /* scaled indexed */ { int shift=0; switch (regs->iir & OPCODE1_MASK) { case OPCODE_LDH_I: shift= 1; break; case OPCODE_LDW_I: shift= 2; break; case OPCODE_LDD_I: case OPCODE_LDDA_I: shift= 3; break; } newbase += (R2(regs->iir)?regs->gr[R2(regs->iir)]:0)<<shift; } else /* simple indexed */ newbase += (R2(regs->iir)?regs->gr[R2(regs->iir)]:0); } break; case 0x13: case 0x1b: modify = 1; newbase += IM14(regs->iir); break; case 0x14: case 0x1c: if (regs->iir&8) { modify = 1; newbase += IM14(regs->iir&~0xe); } break; case 0x16: case 0x1e: modify = 1; newbase += IM14(regs->iir&6); break; case 0x17: case 0x1f: if (regs->iir&4) { modify = 1; newbase += IM14(regs->iir&~4); } break; } /* TODO: make this cleaner... */ switch (regs->iir & OPCODE1_MASK) { case OPCODE_LDH_I: case OPCODE_LDH_S: ret = emulate_ldh(regs, R3(regs->iir)); break; case OPCODE_LDW_I: case OPCODE_LDWA_I: case OPCODE_LDW_S: case OPCODE_LDWA_S: ret = emulate_ldw(regs, R3(regs->iir),0); break; case OPCODE_STH: ret = emulate_sth(regs, R2(regs->iir)); break; case OPCODE_STW: case OPCODE_STWA: ret = emulate_stw(regs, R2(regs->iir),0); break; #ifdef CONFIG_PA20 case OPCODE_LDD_I: case OPCODE_LDDA_I: case OPCODE_LDD_S: case OPCODE_LDDA_S: ret = emulate_ldd(regs, R3(regs->iir),0); break; case OPCODE_STD: case OPCODE_STDA: ret = emulate_std(regs, R2(regs->iir),0); break; #endif case OPCODE_FLDWX: case OPCODE_FLDWS: case OPCODE_FLDWXR: case OPCODE_FLDWSR: flop=1; ret = emulate_ldw(regs,FR3(regs->iir),1); break; case OPCODE_FLDDX: case OPCODE_FLDDS: flop=1; ret = emulate_ldd(regs,R3(regs->iir),1); break; case OPCODE_FSTWX: case OPCODE_FSTWS: case OPCODE_FSTWXR: case OPCODE_FSTWSR: flop=1; ret = emulate_stw(regs,FR3(regs->iir),1); break; case OPCODE_FSTDX: case OPCODE_FSTDS: flop=1; ret = emulate_std(regs,R3(regs->iir),1); break; case OPCODE_LDCD_I: case OPCODE_LDCW_I: case OPCODE_LDCD_S: case OPCODE_LDCW_S: ret = ERR_NOTHANDLED; /* "undefined", but lets kill them. */ break; } #ifdef CONFIG_PA20 switch (regs->iir & OPCODE2_MASK) { case OPCODE_FLDD_L: flop=1; ret = emulate_ldd(regs,R2(regs->iir),1); break; case OPCODE_FSTD_L: flop=1; ret = emulate_std(regs, R2(regs->iir),1); break; #ifdef CONFIG_PA20 case OPCODE_LDD_L: ret = emulate_ldd(regs, R2(regs->iir),0); break; case OPCODE_STD_L: ret = emulate_std(regs, R2(regs->iir),0); break; #endif } #endif switch (regs->iir & OPCODE3_MASK) { case OPCODE_FLDW_L: flop=1; ret = emulate_ldw(regs, R2(regs->iir),0); break; case OPCODE_LDW_M: ret = emulate_ldw(regs, R2(regs->iir),1); break; case OPCODE_FSTW_L: flop=1; ret = emulate_stw(regs, R2(regs->iir),1); break; case OPCODE_STW_M: ret = emulate_stw(regs, R2(regs->iir),0); break; } switch (regs->iir & OPCODE4_MASK) { case OPCODE_LDH_L: ret = emulate_ldh(regs, R2(regs->iir)); break; case OPCODE_LDW_L: case OPCODE_LDWM: ret = emulate_ldw(regs, R2(regs->iir),0); break; case OPCODE_STH_L: ret = emulate_sth(regs, R2(regs->iir)); break; case OPCODE_STW_L: case OPCODE_STWM: ret = emulate_stw(regs, R2(regs->iir),0); break; } if (modify && R1(regs->iir)) regs->gr[R1(regs->iir)] = newbase; if (ret == ERR_NOTHANDLED) printk(KERN_CRIT "Not-handled unaligned insn 0x%08lx\n", regs->iir); DPRINTF("ret = %d\n", ret); if (ret) { printk(KERN_CRIT "Unaligned handler failed, ret = %d\n", ret); die_if_kernel("Unaligned data reference", regs, 28); if (ret == ERR_PAGEFAULT) { si.si_signo = SIGSEGV; si.si_errno = 0; si.si_code = SEGV_MAPERR; si.si_addr = (void __user *)regs->ior; force_sig_info(SIGSEGV, &si, current); } else { force_sigbus: /* couldn't handle it ... */ si.si_signo = SIGBUS; si.si_errno = 0; si.si_code = BUS_ADRALN; si.si_addr = (void __user *)regs->ior; force_sig_info(SIGBUS, &si, current); } return; } /* else we handled it, let life go on. */ regs->gr[0]|=PSW_N; } /* * NB: check_unaligned() is only used for PCXS processors right * now, so we only check for PA1.1 encodings at this point. */ int check_unaligned(struct pt_regs *regs) { unsigned long align_mask; /* Get alignment mask */ align_mask = 0UL; switch (regs->iir & OPCODE1_MASK) { case OPCODE_LDH_I: case OPCODE_LDH_S: case OPCODE_STH: align_mask = 1UL; break; case OPCODE_LDW_I: case OPCODE_LDWA_I: case OPCODE_LDW_S: case OPCODE_LDWA_S: case OPCODE_STW: case OPCODE_STWA: align_mask = 3UL; break; default: switch (regs->iir & OPCODE4_MASK) { case OPCODE_LDH_L: case OPCODE_STH_L: align_mask = 1UL; break; case OPCODE_LDW_L: case OPCODE_LDWM: case OPCODE_STW_L: case OPCODE_STWM: align_mask = 3UL; break; } break; } return (int)(regs->ior & align_mask); }