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6935172: Optimize bit-twiddling in Bits.java

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Transformations to reduce size of bytecode

Reviewed-by: sherman
This commit is contained in:
Based on an idea by Ulf Zibis 2010-06-30 16:11:32 -07:00 committed by Martin Buchholz
parent 3cb2c5c25a
commit cd7e4c8c16
1 changed files with 24 additions and 48 deletions
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72
jdk/src/share/classes/java/io/Bits.java
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@ -41,51 +41,39 @@ class Bits {
}
static char getChar(byte[] b, int off) {
return (char) (((b[off + 1] & 0xFF) << 0) +
((b[off + 0]) << 8));
return (char) ((b[off + 1] & 0xFF) +
(b[off] << 8));
}
static short getShort(byte[] b, int off) {
return (short) (((b[off + 1] & 0xFF) << 0) +
((b[off + 0]) << 8));
return (short) ((b[off + 1] & 0xFF) +
(b[off] << 8));
}
static int getInt(byte[] b, int off) {
return ((b[off + 3] & 0xFF) << 0) +
((b[off + 2] & 0xFF) << 8) +
return ((b[off + 3] & 0xFF) ) +
((b[off + 2] & 0xFF) << 8) +
((b[off + 1] & 0xFF) << 16) +
((b[off + 0]) << 24);
((b[off ] ) << 24);
}
static float getFloat(byte[] b, int off) {
int i = ((b[off + 3] & 0xFF) << 0) +
((b[off + 2] & 0xFF) << 8) +
((b[off + 1] & 0xFF) << 16) +
((b[off + 0]) << 24);
return Float.intBitsToFloat(i);
return Float.intBitsToFloat(getInt(b, off));
}
static long getLong(byte[] b, int off) {
return ((b[off + 7] & 0xFFL) << 0) +
((b[off + 6] & 0xFFL) << 8) +
return ((b[off + 7] & 0xFFL) ) +
((b[off + 6] & 0xFFL) << 8) +
((b[off + 5] & 0xFFL) << 16) +
((b[off + 4] & 0xFFL) << 24) +
((b[off + 3] & 0xFFL) << 32) +
((b[off + 2] & 0xFFL) << 40) +
((b[off + 1] & 0xFFL) << 48) +
(((long) b[off + 0]) << 56);
(((long) b[off]) << 56);
}
static double getDouble(byte[] b, int off) {
long j = ((b[off + 7] & 0xFFL) << 0) +
((b[off + 6] & 0xFFL) << 8) +
((b[off + 5] & 0xFFL) << 16) +
((b[off + 4] & 0xFFL) << 24) +
((b[off + 3] & 0xFFL) << 32) +
((b[off + 2] & 0xFFL) << 40) +
((b[off + 1] & 0xFFL) << 48) +
(((long) b[off + 0]) << 56);
return Double.longBitsToDouble(j);
return Double.longBitsToDouble(getLong(b, off));
}
/*
@ -98,50 +86,38 @@ class Bits {
}
static void putChar(byte[] b, int off, char val) {
b[off + 1] = (byte) (val >>> 0);
b[off + 0] = (byte) (val >>> 8);
b[off + 1] = (byte) (val );
b[off ] = (byte) (val >>> 8);
}
static void putShort(byte[] b, int off, short val) {
b[off + 1] = (byte) (val >>> 0);
b[off + 0] = (byte) (val >>> 8);
b[off + 1] = (byte) (val );
b[off ] = (byte) (val >>> 8);
}
static void putInt(byte[] b, int off, int val) {
b[off + 3] = (byte) (val >>> 0);
b[off + 2] = (byte) (val >>> 8);
b[off + 3] = (byte) (val );
b[off + 2] = (byte) (val >>> 8);
b[off + 1] = (byte) (val >>> 16);
b[off + 0] = (byte) (val >>> 24);
b[off ] = (byte) (val >>> 24);
}
static void putFloat(byte[] b, int off, float val) {
int i = Float.floatToIntBits(val);
b[off + 3] = (byte) (i >>> 0);
b[off + 2] = (byte) (i >>> 8);
b[off + 1] = (byte) (i >>> 16);
b[off + 0] = (byte) (i >>> 24);
putInt(b, off, Float.floatToIntBits(val));
}
static void putLong(byte[] b, int off, long val) {
b[off + 7] = (byte) (val >>> 0);
b[off + 6] = (byte) (val >>> 8);
b[off + 7] = (byte) (val );
b[off + 6] = (byte) (val >>> 8);
b[off + 5] = (byte) (val >>> 16);
b[off + 4] = (byte) (val >>> 24);
b[off + 3] = (byte) (val >>> 32);
b[off + 2] = (byte) (val >>> 40);
b[off + 1] = (byte) (val >>> 48);
b[off + 0] = (byte) (val >>> 56);
b[off ] = (byte) (val >>> 56);
}
static void putDouble(byte[] b, int off, double val) {
long j = Double.doubleToLongBits(val);
b[off + 7] = (byte) (j >>> 0);
b[off + 6] = (byte) (j >>> 8);
b[off + 5] = (byte) (j >>> 16);
b[off + 4] = (byte) (j >>> 24);
b[off + 3] = (byte) (j >>> 32);
b[off + 2] = (byte) (j >>> 40);
b[off + 1] = (byte) (j >>> 48);
b[off + 0] = (byte) (j >>> 56);
putLong(b, off, Double.doubleToLongBits(val));
}
}