bsnes/nall/bit.hpp
Tim Allen 82293c95ae Update to v099r14 release.
byuu says:

Changelog:
- (u)int(max,ptr) abbreviations removed; use _t suffix now [didn't feel
  like they were contributing enough to be worth it]
- cleaned up nall::integer,natural,real functionality
  - toInteger, toNatural, toReal for parsing strings to numbers
  - fromInteger, fromNatural, fromReal for creating strings from numbers
  - (string,Markup::Node,SQL-based-classes)::(integer,natural,real)
    left unchanged
  - template<typename T> numeral(T value, long padding, char padchar)
    -> string for print() formatting
    - deduces integer,natural,real based on T ... cast the value if you
      want to override
    - there still exists binary,octal,hex,pointer for explicit print()
      formatting
- lstring -> string_vector [but using lstring = string_vector; is
  declared]
  - would be nice to remove the using lstring eventually ... but that'd
    probably require 10,000 lines of changes >_>
- format -> string_format [no using here; format was too ambiguous]
- using integer = Integer<sizeof(int)*8>; and using natural =
  Natural<sizeof(uint)*8>; declared
  - for consistency with boolean. These three are meant for creating
    zero-initialized values implicitly (various uses)
- R65816::io() -> idle() and SPC700::io() -> idle() [more clear; frees
  up struct IO {} io; naming]
- SFC CPU, PPU, SMP use struct IO {} io; over struct (Status,Registers) {}
  (status,registers); now
  - still some CPU::Status status values ... they didn't really fit into
    IO functionality ... will have to think about this more
- SFC CPU, PPU, SMP now use step() exclusively instead of addClocks()
  calling into step()
- SFC CPU joypad1_bits, joypad2_bits were unused; killed them
- SFC PPU CGRAM moved into PPU::Screen; since nothing else uses it
- SFC PPU OAM moved into PPU::Object; since nothing else uses it
  - the raw uint8[544] array is gone. OAM::read() constructs values from
    the OAM::Object[512] table now
  - this avoids having to determine how we want to sub-divide the two
    OAM memory sections
  - this also eliminates the OAM::synchronize() functionality
- probably more I'm forgetting

The FPS fluctuations are driving me insane. This WIP went from 128fps to
137fps. Settled on 133.5fps for the final build. But nothing I changed
should have affected performance at all. This level of fluctuation makes
it damn near impossible to know whether I'm speeding things up or slowing
things down with changes.
2016-07-01 21:50:32 +10:00

86 lines
2.2 KiB
C++

#pragma once
#include <nall/stdint.hpp>
namespace nall {
template<uint bits> inline auto uclamp(const uintmax_t x) -> uintmax_t {
enum : uintmax_t { b = 1ull << (bits - 1), y = b * 2 - 1 };
return y + ((x - y) & -(x < y)); //min(x, y);
}
template<uint bits> inline auto uclip(const uintmax_t x) -> uintmax_t {
enum : uintmax_t { b = 1ull << (bits - 1), m = b * 2 - 1 };
return (x & m);
}
template<uint bits> inline auto sclamp(const intmax_t x) -> intmax_t {
enum : intmax_t { b = 1ull << (bits - 1), m = b - 1 };
return (x > m) ? m : (x < -b) ? -b : x;
}
template<uint bits> inline auto sclip(const intmax_t x) -> intmax_t {
enum : uintmax_t { b = 1ull << (bits - 1), m = b * 2 - 1 };
return ((x & m) ^ b) - b;
}
namespace bit {
constexpr inline auto mask(const char* s, uintmax_t sum = 0) -> uintmax_t {
return (
*s == '0' || *s == '1' ? mask(s + 1, (sum << 1) | 1) :
*s == ' ' || *s == '_' ? mask(s + 1, sum) :
*s ? mask(s + 1, sum << 1) :
sum
);
}
constexpr inline auto test(const char* s, uintmax_t sum = 0) -> uintmax_t {
return (
*s == '0' || *s == '1' ? test(s + 1, (sum << 1) | (*s - '0')) :
*s == ' ' || *s == '_' ? test(s + 1, sum) :
*s ? test(s + 1, sum << 1) :
sum
);
}
//lowest(0b1110) == 0b0010
constexpr inline auto lowest(const uintmax_t x) -> uintmax_t {
return x & -x;
}
//clear_lowest(0b1110) == 0b1100
constexpr inline auto clearLowest(const uintmax_t x) -> uintmax_t {
return x & (x - 1);
}
//set_lowest(0b0101) == 0b0111
constexpr inline auto setLowest(const uintmax_t x) -> uintmax_t {
return x | (x + 1);
}
//count number of bits set in a byte
inline auto count(uintmax_t x) -> uint {
uint count = 0;
do count += x & 1; while(x >>= 1);
return count;
}
//return index of the first bit set (or zero of no bits are set)
//first(0b1000) == 3
inline auto first(uintmax_t x) -> uint {
uint first = 0;
while(x) { if(x & 1) break; x >>= 1; first++; }
return first;
}
//round up to next highest single bit:
//round(15) == 16, round(16) == 16, round(17) == 32
inline auto round(uintmax_t x) -> uintmax_t {
if((x & (x - 1)) == 0) return x;
while(x & (x - 1)) x &= x - 1;
return x << 1;
}
}
}