59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
/*
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Copyright 2022 Mattia Giambirtone & Contributors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#ifndef TSOS_UTIL_H
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#define TSOS_UTIL_H
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#include "kernel/types.h"
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// Some handy macros
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/*
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These bitwise tricks *seem* like black
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magic, but they're quite simple: shifting
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the offset by 8 bits moves the high bits 8
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positions down, so we lose the low bits and
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the high bits now fit into a single byte. To
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get the high bits, we do a bitwise and with 0xff
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(11111111 in decimal) leaving us with only the low
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bits: the reason this works is because 0xff (which
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is smaller than our offset), is zero-extended from
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the beginning with zeroes, so when we perform the
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operation the high bits are cancelled out. Neat huh?
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*/
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#define LOW8(x) (u8)(x & 0xff)
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#define HIGH8(x) (u8)(x >> 8)
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/*
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Here we do the same thing, except it's to get the
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low/high 16 bits of a 32-bit value instead
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*/
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#define LOW16(x) (u16)(x & 0xffff)
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#define HIGH16(x) (u16)(LOW16(x >> 16))
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void copystr(const char* source, char* dest, i32 n);
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void memset(byte* dest, byte val, u32 len);
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void itoa(const i32 i, char* a);
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void utoa(const u32 i, char* a);
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#endif |