docs/porting-proto.c.txt

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Dalvik instruction fragments, useful when porting mterp.
 *
 * Compile this and examine the output to see what your compiler generates.
 * This can give you a head start on some of the more complicated operations.
 *
 * Example:
 *   % gcc -c -O2 -save-temps -fverbose-asm porting-proto.c
 *   % less porting-proto.s
 */
#include <stdint.h>

typedef int8_t s1;
typedef uint8_t u1;
typedef int16_t s2;
typedef uint16_t u2;
typedef int32_t s4;
typedef uint32_t u4;
typedef int64_t s8;
typedef uint64_t u8;

s4 iadd32(s4 x, s4 y) { return x + y; }
s8 iadd64(s8 x, s8 y) { return x + y; }
float fadd32(float x, float y) { return x + y; }
double fadd64(double x, double y) { return x + y; }

s4 isub32(s4 x, s4 y) { return x - y; }
s8 isub64(s8 x, s8 y) { return x - y; }
float fsub32(float x, float y) { return x - y; }
double fsub64(double x, double y) { return x - y; }

s4 irsub32lit8(s4 x) { return 25 - x; }

s4 imul32(s4 x, s4 y) { return x * y; }
s8 imul64(s8 x, s8 y) { return x * y; }
float fmul32(float x, float y) { return x * y; }
double fmul64(double x, double y) { return x * y; }

s4 idiv32(s4 x, s4 y) { return x / y; }
s8 idiv64(s8 x, s8 y) { return x / y; }
float fdiv32(float x, float y) { return x / y; }
double fdiv64(double x, double y) { return x / y; }

s4 irem32(s4 x, s4 y) { return x % y; }
s8 irem64(s8 x, s8 y) { return x % y; }

s4 iand32(s4 x, s4 y) { return x & y; }
s8 iand64(s8 x, s8 y) { return x & y; }

s4 ior32(s4 x, s4 y) { return x | y; }
s8 ior64(s8 x, s8 y) { return x | y; }

s4 ixor32(s4 x, s4 y) { return x ^ y; }
s8 ixor64(s8 x, s8 y) { return x ^ y; }

s4 iasl32(s4 x, s4 count) { return x << (count & 0x1f); }
s8 iasl64(s8 x, s4 count) { return x << (count & 0x3f); }

s4 iasr32(s4 x, s4 count) { return x >> (count & 0x1f); }
s8 iasr64(s8 x, s4 count) { return x >> (count & 0x3f); }

s4 ilsr32(s4 x, s4 count) { return ((u4)x) >> (count & 0x1f); } // unsigned
s8 ilsr64(s8 x, s4 count) { return ((u8)x) >> (count & 0x3f); } // unsigned

s4 ineg32(s4 x) { return -x; }
s8 ineg64(s8 x) { return -x; }
float fneg32(float x) { return -x; }
double fneg64(double x) { return -x; }

s4 inot32(s4 x) { return x ^ -1; }
s8 inot64(s8 x) { return x ^ -1LL; }

s4 float2int(float x) { return (s4) x; }
double float2double(float x) { return (double) x; }
s4 double2int(double x) { return (s4) x; }
float double2float(double x) { return (float) x; }

/*
 * ARM lib doesn't clamp large values or NaN the way we want on these two.
 * If the simple version isn't correct, use the long version.  (You can use
 * dalvik/tests/041-narrowing to verify.)
 */
s8 float2long(float x) { return (s8) x; }
s8 float2long_clamp(float x)
{
    static const float kMaxLong = (float)0x7fffffffffffffffULL;
    static const float kMinLong = (float)0x8000000000000000ULL;

    if (x >= kMaxLong) {
        return 0x7fffffffffffffffULL;
    } else if (x <= kMinLong) {
        return 0x8000000000000000ULL;
    } else if (x != x) {
        return 0;
    } else {
        return (s8) x;
    }
}
s8 double2long(double x) { return (s8) x; }
s8 double2long_clamp(double x)
{
    static const double kMaxLong = (double)0x7fffffffffffffffULL;
    static const double kMinLong = (double)0x8000000000000000ULL;

    if (x >= kMaxLong) {
        return 0x7fffffffffffffffULL;
    } else if (x <= kMinLong) {
        return 0x8000000000000000ULL;
    } else if (x != x) {
        return 0;
    } else {
        return (s8) x;
    }
}

s1 int2byte(s4 x) { return (s1) x; }
s2 int2short(s4 x) { return (s2) x; }
u2 int2char(s4 x) { return (u2) x; }
s8 int2long(s4 x) { return (s8) x; }
float int2float(s4 x) { return (float) x; }
double int2double(s4 x) { return (double) x; }

s4 long2int(s8 x) { return (s4) x; }
float long2float(s8 x) { return (float) x; }
double long2double(s8 x) { return (double) x; }

int cmpl_float(float x, float y)
{
    int result;

    if (x == y)
        result = 0;
    else if (x > y)
        result = 1;
    else /* (x < y) or NaN */
        result = -1;
    return result;
}

int cmpg_float(float x, float y)
{
    int result;

    if (x == y)
        result = 0;
    else if (x < y)
        result = -1;
    else /* (x > y) or NaN */
        result = 1;
    return result;
}

int cmpl_double(double x, double y)
{
    int result;

    if (x == y)
        result = 0;
    else if (x > y)
        result = 1;
    else /* (x < y) or NaN */
        result = -1;
    return result;
}

int cmpg_double(double x, double y)
{
    int result;

    if (x == y)
        result = 0;
    else if (x < y)
        result = -1;
    else /* (x > y) or NaN */
        result = 1;
    return result;
}

int cmp_long(s8 x, s8 y)
{
    int result;

    if (x == y)
        result = 0;
    else if (x < y)
        result = -1;
    else /* (x > y) */
        result = 1;
    return result;
}

/* instruction decoding fragments */
u1 unsignedAA(u2 x) { return x >> 8; }
s1 signedAA(u2 x) { return (s4)(x << 16) >> 24; }
s2 signedBB(u2 x) { return (s2) x; }
u1 unsignedA(u2 x) { return (x >> 8) & 0x0f; }
u1 unsignedB(u2 x) { return x >> 12; }

/* some handy immediate constants when working with float/double */
u4 const_43e00000(u4 highword) { return 0x43e00000; }
u4 const_c3e00000(u4 highword) { return 0xc3e00000; }
u4 const_ffc00000(u4 highword) { return 0xffc00000; }
u4 const_41dfffff(u4 highword) { return 0x41dfffff; }
u4 const_c1e00000(u4 highword) { return 0xc1e00000; }

/*
 * Test for some gcc-defined symbols.  If you're frequently switching
 * between different cross-compiler architectures or CPU feature sets,
 * this can help you keep track of which one you're compiling for.
 */
#ifdef __arm__
# warning "found __arm__"
#endif
#ifdef __ARM_EABI__
# warning "found __ARM_EABI__"
#endif
#ifdef __VFP_FP__
# warning "found __VFP_FP__"    /* VFP-format doubles used; may not have VFP */
#endif
#if defined(__VFP_FP__) && !defined(__SOFTFP__)
# warning "VFP in use"
#endif
#ifdef __ARM_ARCH_5TE__
# warning "found __ARM_ARCH_5TE__"
#endif
#ifdef __ARM_ARCH_7A__
# warning "found __ARM_ARCH_7A__"
#endif