443 lines
20 KiB
C
443 lines
20 KiB
C
#ifndef COSMOPOLITAN_LIBC_BITS_H_
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#define COSMOPOLITAN_LIBC_BITS_H_
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#if !(__ASSEMBLER__ + __LINKER__ + 0)
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COSMOPOLITAN_C_START_
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#define CheckUnsigned(x) ((x) / !((typeof(x))(-1) < 0))
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/*───────────────────────────────────────────────────────────────────────────│─╗
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│ cosmopolitan § bits ─╬─│┼
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╚────────────────────────────────────────────────────────────────────────────│*/
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extern const bool kTrue;
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extern const bool kFalse;
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extern const uint8_t kReverseBits[256];
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uint32_t gray(uint32_t) pureconst;
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uint32_t ungray(uint32_t) pureconst;
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unsigned bcdadd(unsigned, unsigned) pureconst;
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unsigned long bcd2i(unsigned long) pureconst;
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unsigned long i2bcd(unsigned long) pureconst;
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void bcxcpy(unsigned char (*)[16], unsigned long);
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int ffs(int) pureconst;
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int ffsl(long int) pureconst;
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int ffsll(long long int) pureconst;
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int fls(int) pureconst;
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int flsl(long int) pureconst;
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int flsll(long long int) pureconst;
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uint8_t bitreverse8(uint8_t) libcesque pureconst;
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uint16_t bitreverse16(uint16_t) libcesque pureconst;
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uint32_t bitreverse32(uint32_t) libcesque pureconst;
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uint64_t bitreverse64(uint64_t) libcesque pureconst;
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unsigned long roundup2pow(unsigned long) libcesque pureconst;
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unsigned long roundup2log(unsigned long) libcesque pureconst;
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unsigned long rounddown2pow(unsigned long) libcesque pureconst;
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unsigned long hamming(unsigned long, unsigned long) pureconst;
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/*───────────────────────────────────────────────────────────────────────────│─╗
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│ cosmopolitan § bits » no assembly required ─╬─│┼
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╚────────────────────────────────────────────────────────────────────────────│*/
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/**
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* Undocumented incantations for ROR, ROL, and SAR.
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*/
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#define ROR(w, k) (CheckUnsigned(w) >> (k) | (w) << (sizeof(w) * 8 - (k)))
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#define ROL(w, k) ((w) << (k) | CheckUnsigned(w) >> (sizeof(w) * 8 - (k)))
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#define SAR(w, k) (((w) & ~(~0u >> (k))) | ((w) >> ((k) & (sizeof(w) * 8 - 1))))
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#define bitreverse8(X) (kReverseBits[(uint8_t)(X)])
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#define bitreverse16(X) \
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((uint16_t)kReverseBits[(uint8_t)(X)] << 010 | \
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kReverseBits[((uint16_t)(X) >> 010) & 0xff])
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#define READ16LE(S) \
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((uint16_t)((unsigned char *)(S))[1] << 010 | \
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(uint16_t)((unsigned char *)(S))[0] << 000)
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#define READ32LE(S) \
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((uint32_t)((unsigned char *)(S))[3] << 030 | \
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(uint32_t)((unsigned char *)(S))[2] << 020 | \
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(uint32_t)((unsigned char *)(S))[1] << 010 | \
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(uint32_t)((unsigned char *)(S))[0] << 000)
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#define READ64LE(S) \
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((uint64_t)((unsigned char *)(S))[7] << 070 | \
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(uint64_t)((unsigned char *)(S))[6] << 060 | \
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(uint64_t)((unsigned char *)(S))[5] << 050 | \
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(uint64_t)((unsigned char *)(S))[4] << 040 | \
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(uint64_t)((unsigned char *)(S))[3] << 030 | \
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(uint64_t)((unsigned char *)(S))[2] << 020 | \
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(uint64_t)((unsigned char *)(S))[1] << 010 | \
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(uint64_t)((unsigned char *)(S))[0] << 000)
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#define READ16BE(S) \
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((uint16_t)((unsigned char *)(S))[0] << 010 | \
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(uint16_t)((unsigned char *)(S))[1] << 000)
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#define READ32BE(S) \
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((uint32_t)((unsigned char *)(S))[0] << 030 | \
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(uint32_t)((unsigned char *)(S))[1] << 020 | \
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(uint32_t)((unsigned char *)(S))[2] << 010 | \
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(uint32_t)((unsigned char *)(S))[3] << 000)
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#define READ64BE(S) \
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((uint64_t)((unsigned char *)(S))[0] << 070 | \
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(uint64_t)((unsigned char *)(S))[1] << 060 | \
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(uint64_t)((unsigned char *)(S))[2] << 050 | \
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(uint64_t)((unsigned char *)(S))[3] << 040 | \
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(uint64_t)((unsigned char *)(S))[4] << 030 | \
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(uint64_t)((unsigned char *)(S))[5] << 020 | \
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(uint64_t)((unsigned char *)(S))[6] << 010 | \
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(uint64_t)((unsigned char *)(S))[7] << 000)
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#define read16le(S) \
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({ \
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unsigned char *Str = (unsigned char *)(S); \
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READ16LE(Str); \
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})
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#define read32le(S) \
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({ \
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unsigned char *Str = (unsigned char *)(S); \
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READ32LE(Str); \
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})
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#define read64le(S) \
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({ \
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unsigned char *Str = (unsigned char *)(S); \
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READ64LE(Str); \
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})
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#define read16be(S) \
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({ \
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unsigned char *Str = (unsigned char *)(S); \
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READ16BE(Str); \
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})
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#define read32be(S) \
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({ \
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unsigned char *Str = (unsigned char *)(S); \
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READ32BE(Str); \
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})
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#define read64be(S) \
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({ \
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unsigned char *Str = (unsigned char *)(S); \
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READ64BE(Str); \
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})
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#define WRITE16LE(P, V) \
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do { \
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uint8_t *Ple = (uint8_t *)(P); \
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uint16_t Vle = (V); \
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Ple[0] = (uint8_t)(Vle >> 000); \
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Ple[1] = (uint8_t)(Vle >> 010); \
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} while (0)
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#define WRITE32LE(P, V) \
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do { \
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uint8_t *Ple = (uint8_t *)(P); \
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uint32_t Vle = (V); \
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Ple[0] = (uint8_t)(Vle >> 000); \
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Ple[1] = (uint8_t)(Vle >> 010); \
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Ple[2] = (uint8_t)(Vle >> 020); \
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Ple[3] = (uint8_t)(Vle >> 030); \
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} while (0)
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#define WRITE64LE(P, V) \
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do { \
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uint8_t *Ple = (uint8_t *)(P); \
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uint64_t Vle = (V); \
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Ple[0] = (uint8_t)(Vle >> 000); \
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Ple[1] = (uint8_t)(Vle >> 010); \
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Ple[2] = (uint8_t)(Vle >> 020); \
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Ple[3] = (uint8_t)(Vle >> 030); \
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Ple[4] = (uint8_t)(Vle >> 040); \
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Ple[5] = (uint8_t)(Vle >> 050); \
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Ple[6] = (uint8_t)(Vle >> 060); \
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Ple[7] = (uint8_t)(Vle >> 070); \
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} while (0)
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/*───────────────────────────────────────────────────────────────────────────│─╗
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│ cosmopolitan § bits » some assembly required ─╬─│┼
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╚────────────────────────────────────────────────────────────────────────────│*/
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/**
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* Constraints for virtual machine flags.
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* @note we beseech clang devs for flag constraints
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*/
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#ifdef __GCC_ASM_FLAG_OUTPUTS__ /* GCC6+ CLANG10+ */
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#define CFLAG_CONSTRAINT "=@ccc"
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#define CFLAG_ASM(OP) OP
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#define ZFLAG_CONSTRAINT "=@ccz"
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#define ZFLAG_ASM(OP) OP
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#define OFLAG_CONSTRAINT "=@cco"
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#define OFLAG_ASM(OP) OP
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#define SFLAG_CONSTRAINT "=@ccs"
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#define SFLAG_ASM(SP) SP
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#define ABOVE_CONSTRAINT "=@cca" /* i.e. !ZF && !CF */
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#define ABOVEFLAG_ASM(OP) OP
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#else
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#define CFLAG_CONSTRAINT "=q"
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#define CFLAG_ASM(OP) OP "\n\tsetc\t%b0"
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#define ZFLAG_CONSTRAINT "=q"
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#define ZFLAG_ASM(OP) OP "\n\tsetz\t%b0"
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#define OFLAG_CONSTRAINT "=q"
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#define OFLAG_ASM(OP) OP "\n\tseto\t%b0"
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#define SFLAG_CONSTRAINT "=q"
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#define SFLAG_ASM(SP) OP "\n\tsets\t%b0"
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#define ABOVE_CONSTRAINT "=@cca"
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#define ABOVEFLAG_ASM(OP) OP "\n\tseta\t%b0"
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#endif
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/**
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* Reads scalar from memory w/ one operation.
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*
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* @param MEM is alignas(𝑘) uint𝑘_t[hasatleast 1] where 𝑘 ∈ {8,16,32,64}
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* @return *(MEM)
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* @note defeats compiler load tearing optimizations
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* @note alignas(𝑘) is implied if compiler knows type
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* @note alignas(𝑘) only avoids multi-core / cross-page edge cases
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* @see Intel's Six-Thousand Page Manual V.3A §8.2.3.1
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* @see atomic_store()
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*/
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#define atomic_load(MEM) \
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({ \
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autotype(MEM) Mem = (MEM); \
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typeof(*Mem) Reg; \
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asm("mov\t%1,%0" : "=r"(Reg) : "m"(*Mem)); \
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Reg; \
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})
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/**
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* Saves scalar to memory w/ one operation.
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*
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* This is guaranteed to happen in either one or zero operations,
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* depending on whether or not it's possible for *(MEM) to be read
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* afterwards. This macro only forbids compiler from using >1 ops.
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*
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* @param MEM is alignas(𝑘) uint𝑘_t[hasatleast 1] where 𝑘 ∈ {8,16,32,64}
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* @param VAL is uint𝑘_t w/ better encoding for immediates (constexpr)
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* @return VAL
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* @note alignas(𝑘) on nexgen32e only needed for end of page gotcha
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* @note alignas(𝑘) is implied if compiler knows type
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* @note needed to defeat store tearing optimizations
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* @see Intel Six-Thousand Page Manual Manual V.3A §8.2.3.1
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* @see atomic_load()
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*/
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#define atomic_store(MEM, VAL) \
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({ \
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autotype(VAL) Val = (VAL); \
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typeof(&Val) Mem = (MEM); \
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asm("mov%z1\t%1,%0" : "=m,m"(*Mem) : "i,r"(Val)); \
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Val; \
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})
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/**
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* Returns true if bit is set in memory.
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*
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* This is a generically-typed Bitset<T> ∀ RAM. This macro is intended
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* to be container-like with optimal machine instruction encoding, cf.
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* machine-agnostic container abstractions. Memory accesses are words.
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* Register allocation can be avoided if BIT is known. Be careful when
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* casting character arrays since that should cause a page fault.
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*
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* @param MEM is uint𝑘_t[] where 𝑘 ∈ {16,32,64} base address
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* @param BIT ∈ [-(2**(𝑘-1)),2**(𝑘-1)) is zero-based index
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* @return true if bit is set, otherwise false
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* @see Intel's Six Thousand Page Manual V.2A 3-113
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* @see bts(), btr(), btc()
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*/
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#define bt(MEM, BIT) \
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({ \
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bool OldBit; \
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if (isconstant(BIT)) { \
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asm(CFLAG_ASM("bt%z1\t%2,%1") \
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: CFLAG_CONSTRAINT(OldBit) \
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: "m"((MEM)[(BIT) / (sizeof((MEM)[0]) * CHAR_BIT)]), \
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"J"((BIT) % (sizeof((MEM)[0]) * CHAR_BIT)) \
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: "cc"); \
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} else if (sizeof((MEM)[0]) == 2) { \
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asm(CFLAG_ASM("bt\t%w2,%1") \
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: CFLAG_CONSTRAINT(OldBit) \
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: "m"((MEM)[0]), "r"(BIT) \
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: "cc"); \
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} else if (sizeof((MEM)[0]) == 4) { \
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asm(CFLAG_ASM("bt\t%k2,%1") \
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: CFLAG_CONSTRAINT(OldBit) \
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: "m"((MEM)[0]), "r"(BIT) \
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: "cc"); \
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} else if (sizeof((MEM)[0]) == 8) { \
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asm(CFLAG_ASM("bt\t%q2,%1") \
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: CFLAG_CONSTRAINT(OldBit) \
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: "m"((MEM)[0]), "r"(BIT) \
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: "cc"); \
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} \
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OldBit; \
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})
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#define bts(MEM, BIT) __BitOp("bts", BIT, MEM) /** bit test and set */
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#define btr(MEM, BIT) __BitOp("btr", BIT, MEM) /** bit test and reset */
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#define btc(MEM, BIT) __BitOp("btc", BIT, MEM) /** bit test and complement */
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#define lockbts(MEM, BIT) __BitOp("lock bts", BIT, MEM)
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#define lockbtr(MEM, BIT) __BitOp("lock btr", BIT, MEM)
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#define lockbtc(MEM, BIT) __BitOp("lock btc", BIT, MEM)
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#define lockinc(MEM) __ArithmeticOp1("lock inc", MEM)
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#define lockdec(MEM) __ArithmeticOp1("lock dec", MEM)
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#define locknot(MEM) __ArithmeticOp1("lock not", MEM)
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#define lockneg(MEM) __ArithmeticOp1("lock neg", MEM)
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#define lockaddeq(MEM, VAL) __ArithmeticOp2("lock add", VAL, MEM)
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#define locksubeq(MEM, VAL) __ArithmeticOp2("lock sub", VAL, MEM)
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#define lockxoreq(MEM, VAL) __ArithmeticOp2("lock xor", VAL, MEM)
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#define lockandeq(MEM, VAL) __ArithmeticOp2("lock and", VAL, MEM)
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#define lockoreq(MEM, VAL) __ArithmeticOp2("lock or", VAL, MEM)
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/**
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* Exchanges *MEMORY into *LOCALVAR w/ one operation.
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*
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* @param MEMORY is uint𝑘_t[hasatleast 1] where 𝑘 ∈ {8,16,32,64}
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* @param LOCALVAR is uint𝑘_t[hasatleast 1]
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* @return LOCALVAR[0]
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* @see xchg()
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*/
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#define lockxchg(MEMORY, LOCALVAR) \
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({ \
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static_assert(typescompatible(typeof(*(MEMORY)), typeof(*(LOCALVAR)))); \
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asm("xchg\t%0,%1" : "+%m"(*(MEMORY)), "+r"(*(LOCALVAR))); \
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*(LOCALVAR); \
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})
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/**
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* Compares and exchanges.
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*
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* @param IFTHING is uint𝑘_t[hasatleast 1] where 𝑘 ∈ {8,16,32,64}
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* @return true if value was exchanged, otherwise false
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* @see lockcmpxchg()
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*/
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#define cmpxchg(IFTHING, ISEQUALTOME, REPLACEITWITHME) \
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({ \
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bool DidIt; \
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asm(ZFLAG_ASM("cmpxchg\t%3,%1") \
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: ZFLAG_CONSTRAINT(DidIt), "+m"(*(IFTHING)), "+a"(*(ISEQUALTOME)) \
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: "r"((typeof(*(IFTHING)))(REPLACEITWITHME)) \
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: "cc"); \
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DidIt; \
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})
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#define ezcmpxchg(IFTHING, ISEQUALTOME, REPLACEITWITHME) \
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({ \
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bool DidIt; \
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autotype(IFTHING) IfThing = (IFTHING); \
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typeof(*IfThing) IsEqualToMe = (ISEQUALTOME); \
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typeof(*IfThing) ReplaceItWithMe = (REPLACEITWITHME); \
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asm(ZFLAG_ASM("cmpxchg\t%3,%1") \
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: ZFLAG_CONSTRAINT(DidIt), "+m"(*IfThing), "+a"(IsEqualToMe) \
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: "r"(ReplaceItWithMe) \
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: "cc"); \
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DidIt; \
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})
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/**
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* Compares and exchanges w/ one operation.
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*
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* @param IFTHING is uint𝑘_t[hasatleast 1] where 𝑘 ∈ {8,16,32,64}
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* @return true if value was exchanged, otherwise false
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* @see lockcmpxchg()
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*/
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#define lockcmpxchg(IFTHING, ISEQUALTOME, REPLACEITWITHME) \
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({ \
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bool DidIt; \
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asm(ZFLAG_ASM("lock cmpxchg\t%3,%1") \
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: ZFLAG_CONSTRAINT(DidIt), "+m"(*(IFTHING)), "+a"(*(ISEQUALTOME)) \
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: "r"((typeof(*(IFTHING)))(REPLACEITWITHME)) \
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: "cc"); \
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DidIt; \
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})
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/**
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* Gets value of extended control register.
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*/
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#define xgetbv(xcr_register_num) \
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({ \
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unsigned hi, lo; \
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asm("xgetbv" : "=d"(hi), "=a"(lo) : "c"(cr_register_num)); \
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(uint64_t) hi << 32 | lo; \
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})
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/**
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* Reads model-specific register.
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* @note programs running as guests won't have authorization
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*/
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#define rdmsr(msr) \
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({ \
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uint32_t lo, hi; \
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asm volatile("rdmsr" : "=a"(lo), "=d"(hi) : "c"(msr)); \
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(uint64_t) hi << 32 | lo; \
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})
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/**
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* Writes model-specific register.
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* @note programs running as guests won't have authorization
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*/
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#define wrmsr(msr, val) \
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do { \
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uint64_t val_ = (val); \
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asm volatile("wrmsr" \
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: /* no outputs */ \
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: "c"(msr), "a"((uint32_t)val_), \
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"d"((uint32_t)(val_ >> 32))); \
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} while (0)
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/**
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* Tells CPU page tables changed for virtual address.
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* @note programs running as guests won't have authorization
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*/
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#define invlpg(MEM) \
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asm volatile("invlpg\t(%0)" : /* no outputs */ : "r"(MEM) : "memory")
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#define IsAddressCanonicalForm(P) \
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({ \
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intptr_t p2 = (intptr_t)(P); \
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(0xffff800000000000l <= p2 && p2 <= 0x00007fffffffffffl); \
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})
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/*───────────────────────────────────────────────────────────────────────────│─╗
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│ cosmopolitan § bits » implementation details ─╬─│┼
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╚────────────────────────────────────────────────────────────────────────────│*/
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#define __ArithmeticOp1(OP, MEM) \
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({ \
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asm(OP "%z0\t%0" : "+m"(*(MEM)) : /* no inputs */ : "cc"); \
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MEM; \
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})
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#define __ArithmeticOp2(OP, VAL, MEM) \
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({ \
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asm(OP "%z0\t%1,%0" : "+m,m"(*(MEM)) : "i,r"(VAL) : "cc"); \
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MEM; \
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})
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#define __BitOp(OP, BIT, MEM) \
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({ \
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bool OldBit; \
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if (isconstant(BIT)) { \
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asm(CFLAG_ASM(OP "%z1\t%2,%1") \
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: CFLAG_CONSTRAINT(OldBit), \
|
||
"+m"((MEM)[(BIT) / (sizeof((MEM)[0]) * CHAR_BIT)]) \
|
||
: "J"((BIT) % (sizeof((MEM)[0]) * CHAR_BIT)) \
|
||
: "cc"); \
|
||
} else if (sizeof((MEM)[0]) == 2) { \
|
||
asm(CFLAG_ASM(OP "\t%w2,%1") \
|
||
: CFLAG_CONSTRAINT(OldBit), "+m"((MEM)[0]) \
|
||
: "r"(BIT) \
|
||
: "cc"); \
|
||
} else if (sizeof((MEM)[0]) == 4) { \
|
||
asm(CFLAG_ASM(OP "\t%k2,%1") \
|
||
: CFLAG_CONSTRAINT(OldBit), "+m"((MEM)[0]) \
|
||
: "r"(BIT) \
|
||
: "cc"); \
|
||
} else if (sizeof((MEM)[0]) == 8) { \
|
||
asm(CFLAG_ASM(OP "\t%q2,%1") \
|
||
: CFLAG_CONSTRAINT(OldBit), "+m"((MEM)[0]) \
|
||
: "r"(BIT) \
|
||
: "cc"); \
|
||
} \
|
||
OldBit; \
|
||
})
|
||
|
||
COSMOPOLITAN_C_END_
|
||
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
|
||
#endif /* COSMOPOLITAN_LIBC_BITS_H_ */
|