Archipelago » qemu

/*

 * Utility compute operations used by translated code.

 *

 * Copyright (c) 2007 Thiemo Seufer

 * Copyright (c) 2007 Jocelyn Mayer

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

/* Note that some of those functions may end up calling libgcc functions,

   depending on the host machine. It is up to the target emulation to

   cope with that. */

/* Binary search for leading zeros.  */

static always_inline int clz32(uint32_t val)

{

    int cnt = 0;

    if (!(val & 0xFFFF0000U)) {

        cnt += 16;

        val <<= 16;

    }

    if (!(val & 0xFF000000U)) {

        cnt += 8;

        val <<= 8;

    }

    if (!(val & 0xF0000000U)) {

        cnt += 4;

        val <<= 4;

    }

    if (!(val & 0xC0000000U)) {

        cnt += 2;

        val <<= 2;

    }

    if (!(val & 0x80000000U)) {

        cnt++;

        val <<= 1;

    }

    if (!(val & 0x80000000U)) {

        cnt++;

    }

    return cnt;

}

static always_inline int clo32(uint32_t val)

{

    return clz32(~val);

}

static always_inline int clz64(uint64_t val)

{

    int cnt = 0;

    if (!(val & 0xFFFFFFFF00000000ULL)) {

        cnt += 32;

        val <<= 32;

    }

    if (!(val & 0xFFFF000000000000ULL)) {

        cnt += 16;

        val <<= 16;

    }

    if (!(val & 0xFF00000000000000ULL)) {

        cnt += 8;

        val <<= 8;

    }

    if (!(val & 0xF000000000000000ULL)) {

        cnt += 4;

        val <<= 4;

    }

    if (!(val & 0xC000000000000000ULL)) {

        cnt += 2;

        val <<= 2;

    }

    if (!(val & 0x8000000000000000ULL)) {

        cnt++;

        val <<= 1;

    }

    if (!(val & 0x8000000000000000ULL)) {

        cnt++;

    }

    return cnt;

}

static always_inline int clo64(uint64_t val)

{

    return clz64(~val);

}