mem_helper.c

/*
 *  S/390 memory access helper routines
 *
 *  Copyright (c) 2009 Ulrich Hecht
 *  Copyright (c) 2009 Alexander Graf
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/address-spaces.h"
#include "exec/helper-proto.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#include "qemu/int128.h"

#if !defined(CONFIG_USER_ONLY)
#include "hw/s390x/storage-keys.h"
#endif

/*****************************************************************************/
/* Softmmu support */
#if !defined(CONFIG_USER_ONLY)

/* try to fill the TLB and return an exception if error. If retaddr is
   NULL, it means that the function was called in C code (i.e. not
   from generated code or from helper.c) */
/* XXX: fix it to restore all registers */
void tlb_fill(CPUState *cs, target_ulong addr, MMUAccessType access_type,
              int mmu_idx, uintptr_t retaddr)
{
    int ret = s390_cpu_handle_mmu_fault(cs, addr, access_type, mmu_idx);
    if (unlikely(ret != 0)) {
        cpu_loop_exit_restore(cs, retaddr);
    }
}

#endif

/* #define DEBUG_HELPER */
#ifdef DEBUG_HELPER
#define HELPER_LOG(x...) qemu_log(x)
#else
#define HELPER_LOG(x...)
#endif

/* Reduce the length so that addr + len doesn't cross a page boundary.  */
static inline uint32_t adj_len_to_page(uint32_t len, uint64_t addr)
{
#ifndef CONFIG_USER_ONLY
    if ((addr & ~TARGET_PAGE_MASK) + len - 1 >= TARGET_PAGE_SIZE) {
        return -addr & ~TARGET_PAGE_MASK;
    }
#endif
    return len;
}

static void fast_memset(CPUS390XState *env, uint64_t dest, uint8_t byte,
                        uint32_t l, uintptr_t ra)
{
    int mmu_idx = cpu_mmu_index(env, false);

    while (l > 0) {
        void *p = tlb_vaddr_to_host(env, dest, MMU_DATA_STORE, mmu_idx);
        if (p) {
            /* Access to the whole page in write mode granted.  */
            uint32_t l_adj = adj_len_to_page(l, dest);
            memset(p, byte, l_adj);
            dest += l_adj;
            l -= l_adj;
        } else {
            /* We failed to get access to the whole page. The next write
               access will likely fill the QEMU TLB for the next iteration.  */
            cpu_stb_data_ra(env, dest, byte, ra);
            dest++;
            l--;
        }
    }
}

static void fast_memmove(CPUS390XState *env, uint64_t dest, uint64_t src,
                         uint32_t l, uintptr_t ra)
{
    int mmu_idx = cpu_mmu_index(env, false);

    while (l > 0) {
        void *src_p = tlb_vaddr_to_host(env, src, MMU_DATA_LOAD, mmu_idx);
        void *dest_p = tlb_vaddr_to_host(env, dest, MMU_DATA_STORE, mmu_idx);
        if (src_p && dest_p) {
            /* Access to both whole pages granted.  */
            uint32_t l_adj = adj_len_to_page(l, src);
            l_adj = adj_len_to_page(l_adj, dest);
            memmove(dest_p, src_p, l_adj);
            src += l_adj;
            dest += l_adj;
            l -= l_adj;
        } else {
            /* We failed to get access to one or both whole pages. The next
               read or write access will likely fill the QEMU TLB for the
               next iteration.  */
            cpu_stb_data_ra(env, dest, cpu_ldub_data_ra(env, src, ra), ra);
            src++;
            dest++;
            l--;
        }
    }
}

/* and on array */
static uint32_t do_helper_nc(CPUS390XState *env, uint32_t l, uint64_t dest,
                             uint64_t src, uintptr_t ra)
{
    uint32_t i;
    uint8_t c = 0;

    HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n",
               __func__, l, dest, src);

    for (i = 0; i <= l; i++) {
        uint8_t x = cpu_ldub_data_ra(env, src + i, ra);
        x &= cpu_ldub_data_ra(env, dest + i, ra);
        c |= x;
        cpu_stb_data_ra(env, dest + i, x, ra);
    }
    return c != 0;
}

uint32_t HELPER(nc)(CPUS390XState *env, uint32_t l, uint64_t dest,
                    uint64_t src)
{
    return do_helper_nc(env, l, dest, src, GETPC());
}

/* xor on array */
static uint32_t do_helper_xc(CPUS390XState *env, uint32_t l, uint64_t dest,
                             uint64_t src, uintptr_t ra)
{
    uint32_t i;
    uint8_t c = 0;

    HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n",
               __func__, l, dest, src);

    /* xor with itself is the same as memset(0) */
    if (src == dest) {
        fast_memset(env, dest, 0, l + 1, ra);
        return 0;
    }

    for (i = 0; i <= l; i++) {
        uint8_t x = cpu_ldub_data_ra(env, src + i, ra);
        x ^= cpu_ldub_data_ra(env, dest + i, ra);
        c |= x;
        cpu_stb_data_ra(env, dest + i, x, ra);
    }
    return c != 0;
}

uint32_t HELPER(xc)(CPUS390XState *env, uint32_t l, uint64_t dest,
                    uint64_t src)
{
    return do_helper_xc(env, l, dest, src, GETPC());
}

/* or on array */
static uint32_t do_helper_oc(CPUS390XState *env, uint32_t l, uint64_t dest,
                             uint64_t src, uintptr_t ra)
{
    uint32_t i;
    uint8_t c = 0;

    HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n",
               __func__, l, dest, src);

    for (i = 0; i <= l; i++) {
        uint8_t x = cpu_ldub_data_ra(env, src + i, ra);
        x |= cpu_ldub_data_ra(env, dest + i, ra);
        c |= x;
        cpu_stb_data_ra(env, dest + i, x, ra);
    }
    return c != 0;
}

uint32_t HELPER(oc)(CPUS390XState *env, uint32_t l, uint64_t dest,
                    uint64_t src)
{
    return do_helper_oc(env, l, dest, src, GETPC());
}

/* memmove */
static uint32_t do_helper_mvc(CPUS390XState *env, uint32_t l, uint64_t dest,
                              uint64_t src, uintptr_t ra)
{
    uint32_t i;

    HELPER_LOG("%s l %d dest %" PRIx64 " src %" PRIx64 "\n",
               __func__, l, dest, src);

    /* mvc and memmove do not behave the same when areas overlap! */
    /* mvc with source pointing to the byte after the destination is the
       same as memset with the first source byte */
    if (dest == src + 1) {
        fast_memset(env, dest, cpu_ldub_data_ra(env, src, ra), l + 1, ra);
    } else if (dest < src || src + l < dest) {
        fast_memmove(env, dest, src, l + 1, ra);
    } else {
        /* slow version with byte accesses which always work */
        for (i = 0; i <= l; i++) {
            uint8_t x = cpu_ldub_data_ra(env, src + i, ra);
            cpu_stb_data_ra(env, dest + i, x, ra);
        }
    }

    return env->cc_op;
}

void HELPER(mvc)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
{
    do_helper_mvc(env, l, dest, src, GETPC());
}

/* move inverse  */
void HELPER(mvcin)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
{
    uintptr_t ra = GETPC();
    int i;

    for (i = 0; i <= l; i++) {
        uint8_t v = cpu_ldub_data_ra(env, src - i, ra);
        cpu_stb_data_ra(env, dest + i, v, ra);
    }
}

/* move numerics  */
void HELPER(mvn)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
{
    uintptr_t ra = GETPC();
    int i;

    for (i = 0; i <= l; i++) {
        uint8_t v = cpu_ldub_data_ra(env, dest + i, ra) & 0xf0;
        v |= cpu_ldub_data_ra(env, src + i, ra) & 0x0f;
        cpu_stb_data_ra(env, dest + i, v, ra);
    }
}

/* move with offset  */
void HELPER(mvo)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
{
    uintptr_t ra = GETPC();
    int len_dest = l >> 4;
    int len_src = l & 0xf;
    uint8_t byte_dest, byte_src;
    int i;

    src += len_src;
    dest += len_dest;

    /* Handle rightmost byte */
    byte_src = cpu_ldub_data_ra(env, src, ra);
    byte_dest = cpu_ldub_data_ra(env, dest, ra);
    byte_dest = (byte_dest & 0x0f) | (byte_src << 4);
    cpu_stb_data_ra(env, dest, byte_dest, ra);

    /* Process remaining bytes from right to left */
    for (i = 1; i <= len_dest; i++) {
        byte_dest = byte_src >> 4;
        if (len_src - i >= 0) {
            byte_src = cpu_ldub_data_ra(env, src - i, ra);
        } else {
            byte_src = 0;
        }
        byte_dest |= byte_src << 4;
        cpu_stb_data_ra(env, dest - i, byte_dest, ra);
    }
}

/* move zones  */
void HELPER(mvz)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)
{
    uintptr_t ra = GETPC();
    int i;

    for (i = 0; i <= l; i++) {
        uint8_t b = cpu_ldub_data_ra(env, dest + i, ra) & 0x0f;
        b |= cpu_ldub_data_ra(env, src + i, ra) & 0xf0;
        cpu_stb_data_ra(env, dest + i, b, ra);
    }
}

/* compare unsigned byte arrays */
static uint32_t do_helper_clc(CPUS390XState *env, uint32_t l, uint64_t s1,
                              uint64_t s2, uintptr_t ra)
{
    uint32_t i;
    uint32_t cc = 0;

    HELPER_LOG("%s l %d s1 %" PRIx64 " s2 %" PRIx64 "\n",
               __func__, l, s1, s2);

    for (i = 0; i <= l; i++) {
        uint8_t x = cpu_ldub_data_ra(env, s1 + i, ra);
        uint8_t y = cpu_ldub_data_ra(env, s2 + i, ra);
        HELPER_LOG("%02x (%c)/%02x (%c) ", x, x, y, y);
        if (x < y) {
            cc = 1;
            break;
        } else if (x > y) {
            cc = 2;
            break;
        }
    }

    HELPER_LOG("\n");
    return cc;
}

uint32_t HELPER(clc)(CPUS390XState *env, uint32_t l, uint64_t s1, uint64_t s2)
{
    return do_helper_clc(env, l, s1, s2, GETPC());
}

/* compare logical under mask */
uint32_t HELPER(clm)(CPUS390XState *env, uint32_t r1, uint32_t mask,
                     uint64_t addr)
{
    uintptr_t ra = GETPC();
    uint32_t cc = 0;

    HELPER_LOG("%s: r1 0x%x mask 0x%x addr 0x%" PRIx64 "\n", __func__, r1,
               mask, addr);

    while (mask) {
        if (mask & 8) {
            uint8_t d = cpu_ldub_data_ra(env, addr, ra);
            uint8_t r = extract32(r1, 24, 8);
            HELPER_LOG("mask 0x%x %02x/%02x (0x%" PRIx64 ") ", mask, r, d,
                       addr);
            if (r < d) {
                cc = 1;
                break;
            } else if (r > d) {
                cc = 2;
                break;
            }
            addr++;
        }
        mask = (mask << 1) & 0xf;
        r1 <<= 8;
    }

    HELPER_LOG("\n");
    return cc;
}

static inline uint64_t wrap_address(CPUS390XState *env, uint64_t a)
{
    if (!(env->psw.mask & PSW_MASK_64)) {
        if (!(env->psw.mask & PSW_MASK_32)) {
            /* 24-Bit mode */
            a &= 0x00ffffff;
        } else {
            /* 31-Bit mode */
            a &= 0x7fffffff;
        }
    }
    return a;
}

static inline uint64_t get_address(CPUS390XState *env, int reg)
{
    return wrap_address(env, env->regs[reg]);
}

static inline void set_address(CPUS390XState *env, int reg, uint64_t address)
{
    if (env->psw.mask & PSW_MASK_64) {
        /* 64-Bit mode */
        env->regs[reg] = address;
    } else {
        if (!(env->psw.mask & PSW_MASK_32)) {
            /* 24-Bit mode. According to the PoO it is implementation
            dependent if bits 32-39 remain unchanged or are set to
            zeros.  Choose the former so that the function can also be
            used for TRT.  */
            env->regs[reg] = deposit64(env->regs[reg], 0, 24, address);
        } else {
            /* 31-Bit mode. According to the PoO it is implementation
            dependent if bit 32 remains unchanged or is set to zero.
            Choose the latter so that the function can also be used for
            TRT.  */
            address &= 0x7fffffff;
            env->regs[reg] = deposit64(env->regs[reg], 0, 32, address);
        }
    }
}

/* search string (c is byte to search, r2 is string, r1 end of string) */
uint64_t HELPER(srst)(CPUS390XState *env, uint64_t r0, uint64_t end,
                      uint64_t str)
{
    uintptr_t ra = GETPC();
    uint32_t len;
    uint8_t v, c = r0;

    str = wrap_address(env, str);
    end = wrap_address(env, end);

    /* Assume for now that R2 is unmodified.  */
    env->retxl = str;

    /* Lest we fail to service interrupts in a timely manner, limit the
       amount of work we're willing to do.  For now, let's cap at 8k.  */
    for (len = 0; len < 0x2000; ++len) {
        if (str + len == end) {
            /* Character not found.  R1 & R2 are unmodified.  */
            env->cc_op = 2;
            return end;
        }
        v = cpu_ldub_data_ra(env, str + len, ra);
        if (v == c) {
            /* Character found.  Set R1 to the location; R2 is unmodified.  */
            env->cc_op = 1;
            return str + len;
        }
    }

    /* CPU-determined bytes processed.  Advance R2 to next byte to process.  */
    env->retxl = str + len;
    env->cc_op = 3;
    return end;
}

/* unsigned string compare (c is string terminator) */
uint64_t HELPER(clst)(CPUS390XState *env, uint64_t c, uint64_t s1, uint64_t s2)
{
    uintptr_t ra = GETPC();
    uint32_t len;

    c = c & 0xff;
    s1 = wrap_address(env, s1);
    s2 = wrap_address(env, s2);

    /* Lest we fail to service interrupts in a timely manner, limit the
       amount of work we're willing to do.  For now, let's cap at 8k.  */
    for (len = 0; len < 0x2000; ++len) {
        uint8_t v1 = cpu_ldub_data_ra(env, s1 + len, ra);
        uint8_t v2 = cpu_ldub_data_ra(env, s2 + len, ra);
        if (v1 == v2) {
            if (v1 == c) {
                /* Equal.  CC=0, and don't advance the registers.  */
                env->cc_op = 0;
                env->retxl = s2;
                return s1;
            }
        } else {
            /* Unequal.  CC={1,2}, and advance the registers.  Note that
               the terminator need not be zero, but the string that contains
               the terminator is by definition "low".  */
            env->cc_op = (v1 == c ? 1 : v2 == c ? 2 : v1 < v2 ? 1 : 2);
            env->retxl = s2 + len;
            return s1 + len;
        }
    }

    /* CPU-determined bytes equal; advance the registers.  */
    env->cc_op = 3;
    env->retxl = s2 + len;
    return s1 + len;
}

/* move page */
uint32_t HELPER(mvpg)(CPUS390XState *env, uint64_t r0, uint64_t r1, uint64_t r2)
{
    /* ??? missing r0 handling, which includes access keys, but more
       importantly optional suppression of the exception!  */
    fast_memmove(env, r1, r2, TARGET_PAGE_SIZE, GETPC());
    return 0; /* data moved */
}

/* string copy (c is string terminator) */
uint64_t HELPER(mvst)(CPUS390XState *env, uint64_t c, uint64_t d, uint64_t s)
{
    uintptr_t ra = GETPC();
    uint32_t len;

    c = c & 0xff;
    d = wrap_address(env, d);
    s = wrap_address(env, s);

    /* Lest we fail to service interrupts in a timely manner, limit the
       amount of work we're willing to do.  For now, let's cap at 8k.  */
    for (len = 0; len < 0x2000; ++len) {
        uint8_t v = cpu_ldub_data_ra(env, s + len, ra);
        cpu_stb_data_ra(env, d + len, v, ra);
        if (v == c) {
            /* Complete.  Set CC=1 and advance R1.  */
            env->cc_op = 1;
            env->retxl = s;
            return d + len;
        }
    }

    /* Incomplete.  Set CC=3 and signal to advance R1 and R2.  */
    env->cc_op = 3;
    env->retxl = s + len;
    return d + len;
}

/* load access registers r1 to r3 from memory at a2 */
void HELPER(lam)(CPUS390XState *env, uint32_t r1, uint64_t a2, uint32_t r3)
{
    uintptr_t ra = GETPC();
    int i;

    for (i = r1;; i = (i + 1) % 16) {
        env->aregs[i] = cpu_ldl_data_ra(env, a2, ra);
        a2 += 4;

        if (i == r3) {
            break;
        }
    }
}

/* store access registers r1 to r3 in memory at a2 */
void HELPER(stam)(CPUS390XState *env, uint32_t r1, uint64_t a2, uint32_t r3)
{
    uintptr_t ra = GETPC();
    int i;

    for (i = r1;; i = (i + 1) % 16) {
        cpu_stl_data_ra(env, a2, env->aregs[i], ra);
        a2 += 4;

        if (i == r3) {
            break;
        }
    }
}

/* move long */
uint32_t HELPER(mvcl)(CPUS390XState *env, uint32_t r1, uint32_t r2)
{
    uintptr_t ra = GETPC();
    uint64_t destlen = env->regs[r1 + 1] & 0xffffff;
    uint64_t dest = get_address(env, r1);
    uint64_t srclen = env->regs[r2 + 1] & 0xffffff;
    uint64_t src = get_address(env, r2);
    uint8_t pad = env->regs[r2 + 1] >> 24;
    uint8_t v;
    uint32_t cc;

    if (destlen == srclen) {
        cc = 0;
    } else if (destlen < srclen) {
        cc = 1;
    } else {
        cc = 2;
    }

    if (srclen > destlen) {
        srclen = destlen;
    }

    for (; destlen && srclen; src++, dest++, destlen--, srclen--) {
        v = cpu_ldub_data_ra(env, src, ra);
        cpu_stb_data_ra(env, dest, v, ra);
    }

    for (; destlen; dest++, destlen--) {
        cpu_stb_data_ra(env, dest, pad, ra);
    }

    env->regs[r1 + 1] = destlen;
    /* can't use srclen here, we trunc'ed it */
    env->regs[r2 + 1] -= src - env->regs[r2];
    set_address(env, r1, dest);
    set_address(env, r2, src);

    return cc;
}

/* move long extended another memcopy insn with more bells and whistles */
uint32_t HELPER(mvcle)(CPUS390XState *env, uint32_t r1, uint64_t a2,
                       uint32_t r3)
{
    uintptr_t ra = GETPC();
    uint64_t destlen = env->regs[r1 + 1];
    uint64_t dest = get_address(env, r1);
    uint64_t srclen = env->regs[r3 + 1];
    uint64_t src = get_address(env, r3);
    uint8_t pad = a2 & 0xff;
    uint8_t v;
    uint32_t cc;

    if (!(env->psw.mask & PSW_MASK_64)) {
        destlen = (uint32_t)destlen;
        srclen = (uint32_t)srclen;
    }

    if (destlen == srclen) {
        cc = 0;
    } else if (destlen < srclen) {
        cc = 1;
    } else {
        cc = 2;
    }

    if (srclen > destlen) {
        srclen = destlen;
    }

    for (; destlen && srclen; src++, dest++, destlen--, srclen--) {
        v = cpu_ldub_data_ra(env, src, ra);
        cpu_stb_data_ra(env, dest, v, ra);
    }

    for (; destlen; dest++, destlen--) {
        cpu_stb_data_ra(env, dest, pad, ra);
    }

    env->regs[r1 + 1] = destlen;
    /* can't use srclen here, we trunc'ed it */
    /* FIXME: 31-bit mode! */
    env->regs[r3 + 1] -= src - env->regs[r3];
    set_address(env, r1, dest);
    set_address(env, r3, src);

    return cc;
}

/* compare logical long extended memcompare insn with padding */
uint32_t HELPER(clcle)(CPUS390XState *env, uint32_t r1, uint64_t a2,
                       uint32_t r3)
{
    uintptr_t ra = GETPC();
    uint64_t destlen = env->regs[r1 + 1];
    uint64_t dest = get_address(env, r1);
    uint64_t srclen = env->regs[r3 + 1];
    uint64_t src = get_address(env, r3);
    uint8_t pad = a2 & 0xff;
    uint32_t cc = 0;

    if (!(destlen || srclen)) {
        return cc;
    }

    if (srclen > destlen) {
        srclen = destlen;
    }

    for (; destlen || srclen; src++, dest++, destlen--, srclen--) {
        uint8_t v1 = srclen ? cpu_ldub_data_ra(env, src, ra) : pad;
        uint8_t v2 = destlen ? cpu_ldub_data_ra(env, dest, ra) : pad;
        if (v1 != v2) {
            cc = (v1 < v2) ? 1 : 2;
            break;
        }
    }

    env->regs[r1 + 1] = destlen;
    /* can't use srclen here, we trunc'ed it */
    env->regs[r3 + 1] -= src - env->regs[r3];
    set_address(env, r1, dest);
    set_address(env, r3, src);

    return cc;
}

/* checksum */
uint64_t HELPER(cksm)(CPUS390XState *env, uint64_t r1,
                      uint64_t src, uint64_t src_len)
{
    uintptr_t ra = GETPC();
    uint64_t max_len, len;
    uint64_t cksm = (uint32_t)r1;

    /* Lest we fail to service interrupts in a timely manner, limit the
       amount of work we're willing to do.  For now, let's cap at 8k.  */
    max_len = (src_len > 0x2000 ? 0x2000 : src_len);

    /* Process full words as available.  */
    for (len = 0; len + 4 <= max_len; len += 4, src += 4) {
        cksm += (uint32_t)cpu_ldl_data_ra(env, src, ra);
    }

    switch (max_len - len) {
    case 1:
        cksm += cpu_ldub_data_ra(env, src, ra) << 24;
        len += 1;
        break;
    case 2:
        cksm += cpu_lduw_data_ra(env, src, ra) << 16;
        len += 2;
        break;
    case 3:
        cksm += cpu_lduw_data_ra(env, src, ra) << 16;
        cksm += cpu_ldub_data_ra(env, src + 2, ra) << 8;
        len += 3;
        break;
    }

    /* Fold the carry from the checksum.  Note that we can see carry-out
       during folding more than once (but probably not more than twice).  */
    while (cksm > 0xffffffffull) {
        cksm = (uint32_t)cksm + (cksm >> 32);
    }

    /* Indicate whether or not we've processed everything.  */
    env->cc_op = (len == src_len ? 0 : 3);

    /* Return both cksm and processed length.  */
    env->retxl = cksm;
    return len;
}

void HELPER(pack)(CPUS390XState *env, uint32_t len, uint64_t dest, uint64_t src)
{
    uintptr_t ra = GETPC();
    int len_dest = len >> 4;
    int len_src = len & 0xf;
    uint8_t b;

    dest += len_dest;
    src += len_src;

    /* last byte is special, it only flips the nibbles */
    b = cpu_ldub_data_ra(env, src, ra);
    cpu_stb_data_ra(env, dest, (b << 4) | (b >> 4), ra);
    src--;
    len_src--;

    /* now pack every value */
    while (len_dest >= 0) {
        b = 0;

        if (len_src > 0) {
            b = cpu_ldub_data_ra(env, src, ra) & 0x0f;
            src--;
            len_src--;
        }
        if (len_src > 0) {
            b |= cpu_ldub_data_ra(env, src, ra) << 4;
            src--;
            len_src--;
        }

        len_dest--;
        dest--;
        cpu_stb_data_ra(env, dest, b, ra);
    }
}

void HELPER(unpk)(CPUS390XState *env, uint32_t len, uint64_t dest,
                  uint64_t src)
{
    uintptr_t ra = GETPC();
    int len_dest = len >> 4;
    int len_src = len & 0xf;
    uint8_t b;
    int second_nibble = 0;

    dest += len_dest;
    src += len_src;

    /* last byte is special, it only flips the nibbles */
    b = cpu_ldub_data_ra(env, src, ra);
    cpu_stb_data_ra(env, dest, (b << 4) | (b >> 4), ra);
    src--;
    len_src--;

    /* now pad every nibble with 0xf0 */

    while (len_dest > 0) {
        uint8_t cur_byte = 0;

        if (len_src > 0) {
            cur_byte = cpu_ldub_data_ra(env, src, ra);
        }

        len_dest--;
        dest--;

        /* only advance one nibble at a time */
        if (second_nibble) {
            cur_byte >>= 4;
            len_src--;
            src--;
        }
        second_nibble = !second_nibble;

        /* digit */
        cur_byte = (cur_byte & 0xf);
        /* zone bits */
        cur_byte |= 0xf0;

        cpu_stb_data_ra(env, dest, cur_byte, ra);
    }
}

static uint32_t do_helper_tr(CPUS390XState *env, uint32_t len, uint64_t array,
                             uint64_t trans, uintptr_t ra)
{
    uint32_t i;

    for (i = 0; i <= len; i++) {
        uint8_t byte = cpu_ldub_data_ra(env, array + i, ra);
        uint8_t new_byte = cpu_ldub_data_ra(env, trans + byte, ra);
        cpu_stb_data_ra(env, array + i, new_byte, ra);
    }

    return env->cc_op;
}

void HELPER(tr)(CPUS390XState *env, uint32_t len, uint64_t array,
                uint64_t trans)
{
    do_helper_tr(env, len, array, trans, GETPC());
}

uint64_t HELPER(tre)(CPUS390XState *env, uint64_t array,
                     uint64_t len, uint64_t trans)
{
    uintptr_t ra = GETPC();
    uint8_t end = env->regs[0] & 0xff;
    uint64_t l = len;
    uint64_t i;
    uint32_t cc = 0;

    if (!(env->psw.mask & PSW_MASK_64)) {
        array &= 0x7fffffff;
        l = (uint32_t)l;
    }

    /* Lest we fail to service interrupts in a timely manner, limit the
       amount of work we're willing to do.  For now, let's cap at 8k.  */
    if (l > 0x2000) {
        l = 0x2000;
        cc = 3;
    }

    for (i = 0; i < l; i++) {
        uint8_t byte, new_byte;

        byte = cpu_ldub_data_ra(env, array + i, ra);

        if (byte == end) {
            cc = 1;
            break;
        }

        new_byte = cpu_ldub_data_ra(env, trans + byte, ra);
        cpu_stb_data_ra(env, array + i, new_byte, ra);
    }

    env->cc_op = cc;
    env->retxl = len - i;
    return array + i;
}

static uint32_t do_helper_trt(CPUS390XState *env, uint32_t len, uint64_t array,
                              uint64_t trans, uintptr_t ra)
{
    uint32_t i;

    for (i = 0; i <= len; i++) {
        uint8_t byte = cpu_ldub_data_ra(env, array + i, ra);
        uint8_t sbyte = cpu_ldub_data_ra(env, trans + byte, ra);

        if (sbyte != 0) {
            set_address(env, 1, array + i);
            env->regs[2] = deposit64(env->regs[2], 0, 8, sbyte);
            return (i == len) ? 2 : 1;
        }
    }

    return 0;
}

uint32_t HELPER(trt)(CPUS390XState *env, uint32_t len, uint64_t array,
                     uint64_t trans)
{
    return do_helper_trt(env, len, array, trans, GETPC());
}

void HELPER(cdsg)(CPUS390XState *env, uint64_t addr,
                  uint32_t r1, uint32_t r3)
{
    uintptr_t ra = GETPC();
    Int128 cmpv = int128_make128(env->regs[r1 + 1], env->regs[r1]);
    Int128 newv = int128_make128(env->regs[r3 + 1], env->regs[r3]);
    Int128 oldv;
    bool fail;

    if (parallel_cpus) {
#ifndef CONFIG_ATOMIC128
        cpu_loop_exit_atomic(ENV_GET_CPU(env), ra);
#else
        int mem_idx = cpu_mmu_index(env, false);
        TCGMemOpIdx oi = make_memop_idx(MO_TEQ | MO_ALIGN_16, mem_idx);
        oldv = helper_atomic_cmpxchgo_be_mmu(env, addr, cmpv, newv, oi, ra);
        fail = !int128_eq(oldv, cmpv);
#endif
    } else {
        uint64_t oldh, oldl;

        oldh = cpu_ldq_data_ra(env, addr + 0, ra);
        oldl = cpu_ldq_data_ra(env, addr + 8, ra);

        oldv = int128_make128(oldl, oldh);
        fail = !int128_eq(oldv, cmpv);
        if (fail) {
            newv = oldv;
        }

        cpu_stq_data_ra(env, addr + 0, int128_gethi(newv), ra);
        cpu_stq_data_ra(env, addr + 8, int128_getlo(newv), ra);
    }

    env->cc_op = fail;
    env->regs[r1] = int128_gethi(oldv);
    env->regs[r1 + 1] = int128_getlo(oldv);
}

#if !defined(CONFIG_USER_ONLY)
void HELPER(lctlg)(CPUS390XState *env, uint32_t r1, uint64_t a2, uint32_t r3)
{
    uintptr_t ra = GETPC();
    S390CPU *cpu = s390_env_get_cpu(env);
    bool PERchanged = false;
    uint64_t src = a2;
    uint32_t i;

    for (i = r1;; i = (i + 1) % 16) {
        uint64_t val = cpu_ldq_data_ra(env, src, ra);
        if (env->cregs[i] != val && i >= 9 && i <= 11) {
            PERchanged = true;
        }
        env->cregs[i] = val;
        HELPER_LOG("load ctl %d from 0x%" PRIx64 " == 0x%" PRIx64 "\n",
                   i, src, val);
        src += sizeof(uint64_t);

        if (i == r3) {
            break;
        }
    }

    if (PERchanged && env->psw.mask & PSW_MASK_PER) {
        s390_cpu_recompute_watchpoints(CPU(cpu));
    }

    tlb_flush(CPU(cpu));
}

void HELPER(lctl)(CPUS390XState *env, uint32_t r1, uint64_t a2, uint32_t r3)
{
    uintptr_t ra = GETPC();
    S390CPU *cpu = s390_env_get_cpu(env);
    bool PERchanged = false;
    uint64_t src = a2;
    uint32_t i;

    for (i = r1;; i = (i + 1) % 16) {
        uint32_t val = cpu_ldl_data_ra(env, src, ra);
        if ((uint32_t)env->cregs[i] != val && i >= 9 && i <= 11) {
            PERchanged = true;
        }
        env->cregs[i] = deposit64(env->cregs[i], 0, 32, val);
        HELPER_LOG("load ctl %d from 0x%" PRIx64 " == 0x%x\n", i, src, val);
        src += sizeof(uint32_t);

        if (i == r3) {
            break;
        }
    }

    if (PERchanged && env->psw.mask & PSW_MASK_PER) {
        s390_cpu_recompute_watchpoints(CPU(cpu));
    }

    tlb_flush(CPU(cpu));
}

void HELPER(stctg)(CPUS390XState *env, uint32_t r1, uint64_t a2, uint32_t r3)
{
    uintptr_t ra = GETPC();
    uint64_t dest = a2;
    uint32_t i;

    for (i = r1;; i = (i + 1) % 16) {
        cpu_stq_data_ra(env, dest, env->cregs[i], ra);
        dest += sizeof(uint64_t);

        if (i == r3) {
            break;
        }
    }
}

void HELPER(stctl)(CPUS390XState *env, uint32_t r1, uint64_t a2, uint32_t r3)
{
    uintptr_t ra = GETPC();
    uint64_t dest = a2;
    uint32_t i;

    for (i = r1;; i = (i + 1) % 16) {
        cpu_stl_data_ra(env, dest, env->cregs[i], ra);
        dest += sizeof(uint32_t);

        if (i == r3) {
            break;
        }
    }
}

uint32_t HELPER(testblock)(CPUS390XState *env, uint64_t real_addr)
{
    uintptr_t ra = GETPC();
    CPUState *cs = CPU(s390_env_get_cpu(env));
    uint64_t abs_addr;
    int i;

    real_addr = wrap_address(env, real_addr);
    abs_addr = mmu_real2abs(env, real_addr) & TARGET_PAGE_MASK;
    if (!address_space_access_valid(&address_space_memory, abs_addr,
                                    TARGET_PAGE_SIZE, true)) {
        cpu_restore_state(cs, ra);
        program_interrupt(env, PGM_ADDRESSING, 4);
        return 1;
    }

    /* Check low-address protection */
    if ((env->cregs[0] & CR0_LOWPROT) && real_addr < 0x2000) {
        cpu_restore_state(cs, ra);
        program_interrupt(env, PGM_PROTECTION, 4);
        return 1;
    }

    for (i = 0; i < TARGET_PAGE_SIZE; i += 8) {
        stq_phys(cs->as, abs_addr + i, 0);
    }

    return 0;
}

uint32_t HELPER(tprot)(uint64_t a1, uint64_t a2)
{
    /* XXX implement */
    return 0;
}

/* insert storage key extended */
uint64_t HELPER(iske)(CPUS390XState *env, uint64_t r2)
{
    static S390SKeysState *ss;
    static S390SKeysClass *skeyclass;
    uint64_t addr = wrap_address(env, r2);
    uint8_t key;

    if (addr > ram_size) {
        return 0;
    }

    if (unlikely(!ss)) {
        ss = s390_get_skeys_device();
        skeyclass = S390_SKEYS_GET_CLASS(ss);
    }

    if (skeyclass->get_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key)) {
        return 0;
    }
    return key;
}

/* set storage key extended */
void HELPER(sske)(CPUS390XState *env, uint64_t r1, uint64_t r2)
{
    static S390SKeysState *ss;
    static S390SKeysClass *skeyclass;
    uint64_t addr = wrap_address(env, r2);
    uint8_t key;

    if (addr > ram_size) {
        return;
    }

    if (unlikely(!ss)) {
        ss = s390_get_skeys_device();
        skeyclass = S390_SKEYS_GET_CLASS(ss);
    }

    key = (uint8_t) r1;
    skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
}

/* reset reference bit extended */
uint32_t HELPER(rrbe)(CPUS390XState *env, uint64_t r2)
{
    static S390SKeysState *ss;
    static S390SKeysClass *skeyclass;
    uint8_t re, key;

    if (r2 > ram_size) {
        return 0;
    }

    if (unlikely(!ss)) {
        ss = s390_get_skeys_device();
        skeyclass = S390_SKEYS_GET_CLASS(ss);
    }

    if (skeyclass->get_skeys(ss, r2 / TARGET_PAGE_SIZE, 1, &key)) {
        return 0;
    }

    re = key & (SK_R | SK_C);
    key &= ~SK_R;

    if (skeyclass->set_skeys(ss, r2 / TARGET_PAGE_SIZE, 1, &key)) {
        return 0;
    }

    /*
     * cc
     *
     * 0  Reference bit zero; change bit zero
     * 1  Reference bit zero; change bit one
     * 2  Reference bit one; change bit zero
     * 3  Reference bit one; change bit one
     */

    return re >> 1;
}

uint32_t HELPER(mvcs)(CPUS390XState *env, uint64_t l, uint64_t a1, uint64_t a2)
{
    uintptr_t ra = GETPC();
    int cc = 0, i;

    HELPER_LOG("%s: %16" PRIx64 " %16" PRIx64 " %16" PRIx64 "\n",
               __func__, l, a1, a2);

    if (l > 256) {
        /* max 256 */
        l = 256;
        cc = 3;
    }

    /* XXX replace w/ memcpy */
    for (i = 0; i < l; i++) {
        uint8_t x = cpu_ldub_primary_ra(env, a2 + i, ra);
        cpu_stb_secondary_ra(env, a1 + i, x, ra);
    }

    return cc;
}

uint32_t HELPER(mvcp)(CPUS390XState *env, uint64_t l, uint64_t a1, uint64_t a2)
{
    uintptr_t ra = GETPC();
    int cc = 0, i;

    HELPER_LOG("%s: %16" PRIx64 " %16" PRIx64 " %16" PRIx64 "\n",
               __func__, l, a1, a2);

    if (l > 256) {
        /* max 256 */
        l = 256;
        cc = 3;
    }

    /* XXX replace w/ memcpy */
    for (i = 0; i < l; i++) {
        uint8_t x = cpu_ldub_secondary_ra(env, a2 + i, ra);
        cpu_stb_primary_ra(env, a1 + i, x, ra);
    }

    return cc;
}

/* invalidate pte */
void HELPER(ipte)(CPUS390XState *env, uint64_t pto, uint64_t vaddr,
                  uint32_t m4)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));
    uint64_t page = vaddr & TARGET_PAGE_MASK;
    uint64_t pte_addr, pte;

    /* Compute the page table entry address */
    pte_addr = (pto & _SEGMENT_ENTRY_ORIGIN);
    pte_addr += (vaddr & VADDR_PX) >> 9;

    /* Mark the page table entry as invalid */
    pte = ldq_phys(cs->as, pte_addr);
    pte |= _PAGE_INVALID;
    stq_phys(cs->as, pte_addr, pte);

    /* XXX we exploit the fact that Linux passes the exact virtual
       address here - it's not obliged to! */
    /* XXX: the LC bit should be considered as 0 if the local-TLB-clearing
       facility is not installed.  */
    if (m4 & 1) {
        tlb_flush_page(cs, page);
    } else {
        tlb_flush_page_all_cpus_synced(cs, page);
    }

    /* XXX 31-bit hack */
    if (m4 & 1) {
        tlb_flush_page(cs, page ^ 0x80000000);
    } else {
        tlb_flush_page_all_cpus_synced(cs, page ^ 0x80000000);
    }
}

/* flush local tlb */
void HELPER(ptlb)(CPUS390XState *env)
{
    S390CPU *cpu = s390_env_get_cpu(env);

    tlb_flush(CPU(cpu));
}

/* flush global tlb */
void HELPER(purge)(CPUS390XState *env)
{
    S390CPU *cpu = s390_env_get_cpu(env);

    tlb_flush_all_cpus_synced(CPU(cpu));
}

/* load using real address */
uint64_t HELPER(lura)(CPUS390XState *env, uint64_t addr)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    return (uint32_t)ldl_phys(cs->as, wrap_address(env, addr));
}

uint64_t HELPER(lurag)(CPUS390XState *env, uint64_t addr)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    return ldq_phys(cs->as, wrap_address(env, addr));
}

/* store using real address */
void HELPER(stura)(CPUS390XState *env, uint64_t addr, uint64_t v1)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    stl_phys(cs->as, wrap_address(env, addr), (uint32_t)v1);

    if ((env->psw.mask & PSW_MASK_PER) &&
        (env->cregs[9] & PER_CR9_EVENT_STORE) &&
        (env->cregs[9] & PER_CR9_EVENT_STORE_REAL)) {
        /* PSW is saved just before calling the helper.  */
        env->per_address = env->psw.addr;
        env->per_perc_atmid = PER_CODE_EVENT_STORE_REAL | get_per_atmid(env);
    }
}

void HELPER(sturg)(CPUS390XState *env, uint64_t addr, uint64_t v1)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    stq_phys(cs->as, wrap_address(env, addr), v1);

    if ((env->psw.mask & PSW_MASK_PER) &&
        (env->cregs[9] & PER_CR9_EVENT_STORE) &&
        (env->cregs[9] & PER_CR9_EVENT_STORE_REAL)) {
        /* PSW is saved just before calling the helper.  */
        env->per_address = env->psw.addr;
        env->per_perc_atmid = PER_CODE_EVENT_STORE_REAL | get_per_atmid(env);
    }
}

/* load real address */
uint64_t HELPER(lra)(CPUS390XState *env, uint64_t addr)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));
    uint32_t cc = 0;
    uint64_t asc = env->psw.mask & PSW_MASK_ASC;
    uint64_t ret;
    int old_exc, flags;

    /* XXX incomplete - has more corner cases */
    if (!(env->psw.mask & PSW_MASK_64) && (addr >> 32)) {
        cpu_restore_state(cs, GETPC());
        program_interrupt(env, PGM_SPECIAL_OP, 2);
    }

    old_exc = cs->exception_index;
    if (mmu_translate(env, addr, 0, asc, &ret, &flags, true)) {
        cc = 3;
    }
    if (cs->exception_index == EXCP_PGM) {
        ret = env->int_pgm_code | 0x80000000;
    } else {
        ret |= addr & ~TARGET_PAGE_MASK;
    }
    cs->exception_index = old_exc;

    env->cc_op = cc;
    return ret;
}
#endif

/* Execute instruction.  This instruction executes an insn modified with
   the contents of r1.  It does not change the executed instruction in memory;
   it does not change the program counter.

   Perform this by recording the modified instruction in env->ex_value.
   This will be noticed by cpu_get_tb_cpu_state and thus tb translation.
*/
void HELPER(ex)(CPUS390XState *env, uint32_t ilen, uint64_t r1, uint64_t addr)
{
    uint64_t insn = cpu_lduw_code(env, addr);
    uint8_t opc = insn >> 8;

    /* Or in the contents of R1[56:63].  */
    insn |= r1 & 0xff;

    /* Load the rest of the instruction.  */
    insn <<= 48;
    switch (get_ilen(opc)) {
    case 2:
        break;
    case 4:
        insn |= (uint64_t)cpu_lduw_code(env, addr + 2) << 32;
        break;
    case 6:
        insn |= (uint64_t)(uint32_t)cpu_ldl_code(env, addr + 2) << 16;
        break;
    default:
        g_assert_not_reached();
    }

    /* The very most common cases can be sped up by avoiding a new TB.  */
    if ((opc & 0xf0) == 0xd0) {
        typedef uint32_t (*dx_helper)(CPUS390XState *, uint32_t, uint64_t,
                                      uint64_t, uintptr_t);
        static const dx_helper dx[16] = {
            [0x2] = do_helper_mvc,
            [0x4] = do_helper_nc,
            [0x5] = do_helper_clc,
            [0x6] = do_helper_oc,
            [0x7] = do_helper_xc,
            [0xc] = do_helper_tr,
            [0xd] = do_helper_trt,
        };
        dx_helper helper = dx[opc & 0xf];

        if (helper) {
            uint32_t l = extract64(insn, 48, 8);
            uint32_t b1 = extract64(insn, 44, 4);
            uint32_t d1 = extract64(insn, 32, 12);
            uint32_t b2 = extract64(insn, 28, 4);
            uint32_t d2 = extract64(insn, 16, 12);
            uint64_t a1 = wrap_address(env, env->regs[b1] + d1);
            uint64_t a2 = wrap_address(env, env->regs[b2] + d2);

            env->cc_op = helper(env, l, a1, a2, 0);
            env->psw.addr += ilen;
            return;
        }
    } else if (opc == 0x0a) {
        env->int_svc_code = extract64(insn, 48, 8);
        env->int_svc_ilen = ilen;
        helper_exception(env, EXCP_SVC);
        g_assert_not_reached();
    }

    /* Record the insn we want to execute as well as the ilen to use
       during the execution of the target insn.  This will also ensure
       that ex_value is non-zero, which flags that we are in a state
       that requires such execution.  */
    env->ex_value = insn | ilen;
}