[clang] d9cb37c - [Headers][X86] Add macro descriptions to ia32intrin.h (#78613)
via cfe-commits
cfe-commits at lists.llvm.org
Mon Jan 22 07:38:38 PST 2024
Author: Paul T Robinson
Date: 2024-01-22T07:38:33-08:00
New Revision: d9cb37c9045bb0b3692d6faaeac43150a26e42e4
URL: https://github.com/llvm/llvm-project/commit/d9cb37c9045bb0b3692d6faaeac43150a26e42e4
DIFF: https://github.com/llvm/llvm-project/commit/d9cb37c9045bb0b3692d6faaeac43150a26e42e4.diff
LOG: [Headers][X86] Add macro descriptions to ia32intrin.h (#78613)
These are largely copy-pasted from the corresponding function
descriptions. Updated _rdtsc definition because it was just plain wrong.
Added:
Modified:
clang/lib/Headers/ia32intrin.h
Removed:
################################################################################
diff --git a/clang/lib/Headers/ia32intrin.h b/clang/lib/Headers/ia32intrin.h
index 7d5fede61ce859..1b979770e19623 100644
--- a/clang/lib/Headers/ia32intrin.h
+++ b/clang/lib/Headers/ia32intrin.h
@@ -37,6 +37,7 @@
/// \param __A
/// A 32-bit integer operand.
/// \returns A 32-bit integer containing the bit number.
+/// \see _bit_scan_forward
static __inline__ int __DEFAULT_FN_ATTRS_CONSTEXPR
__bsfd(int __A) {
return __builtin_ctz((unsigned int)__A);
@@ -53,6 +54,7 @@ __bsfd(int __A) {
/// \param __A
/// A 32-bit integer operand.
/// \returns A 32-bit integer containing the bit number.
+/// \see _bit_scan_reverse
static __inline__ int __DEFAULT_FN_ATTRS_CONSTEXPR
__bsrd(int __A) {
return 31 - __builtin_clz((unsigned int)__A);
@@ -88,7 +90,40 @@ _bswap(int __A) {
return (int)__builtin_bswap32((unsigned int)__A);
}
+/// Find the first set bit starting from the lsb. Result is undefined if
+/// input is 0.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// int _bit_scan_forward(int A);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c BSF instruction or the
+/// \c TZCNT instruction.
+///
+/// \param A
+/// A 32-bit integer operand.
+/// \returns A 32-bit integer containing the bit number.
+/// \see __bsfd
#define _bit_scan_forward(A) __bsfd((A))
+
+/// Find the first set bit starting from the msb. Result is undefined if
+/// input is 0.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// int _bit_scan_reverse(int A);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c BSR instruction or the
+/// \c LZCNT instruction and an \c XOR.
+///
+/// \param A
+/// A 32-bit integer operand.
+/// \returns A 32-bit integer containing the bit number.
+/// \see __bsrd
#define _bit_scan_reverse(A) __bsrd((A))
#ifdef __x86_64__
@@ -134,13 +169,29 @@ __bsrq(long long __A) {
/// \param __A
/// A 64-bit integer operand.
/// \returns A 64-bit integer containing the swapped bytes.
+/// \see _bswap64
static __inline__ long long __DEFAULT_FN_ATTRS_CONSTEXPR
__bswapq(long long __A) {
return (long long)__builtin_bswap64((unsigned long long)__A);
}
+/// Swaps the bytes in the input. Converting little endian to big endian or
+/// vice versa.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// long long _bswap64(long long A);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c BSWAP instruction.
+///
+/// \param A
+/// A 64-bit integer operand.
+/// \returns A 64-bit integer containing the swapped bytes.
+/// \see __bswapq
#define _bswap64(A) __bswapq((A))
-#endif
+#endif /* __x86_64__ */
/// Counts the number of bits in the source operand having a value of 1.
///
@@ -153,12 +204,29 @@ __bswapq(long long __A) {
/// An unsigned 32-bit integer operand.
/// \returns A 32-bit integer containing the number of bits with value 1 in the
/// source operand.
+/// \see _popcnt32
static __inline__ int __DEFAULT_FN_ATTRS_CONSTEXPR
__popcntd(unsigned int __A)
{
return __builtin_popcount(__A);
}
+/// Counts the number of bits in the source operand having a value of 1.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// int _popcnt32(int A);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c POPCNT instruction or a
+/// a sequence of arithmetic and logic ops to calculate it.
+///
+/// \param A
+/// An unsigned 32-bit integer operand.
+/// \returns A 32-bit integer containing the number of bits with value 1 in the
+/// source operand.
+/// \see __popcntd
#define _popcnt32(A) __popcntd((A))
#ifdef __x86_64__
@@ -173,12 +241,29 @@ __popcntd(unsigned int __A)
/// An unsigned 64-bit integer operand.
/// \returns A 64-bit integer containing the number of bits with value 1 in the
/// source operand.
+/// \see _popcnt64
static __inline__ long long __DEFAULT_FN_ATTRS_CONSTEXPR
__popcntq(unsigned long long __A)
{
return __builtin_popcountll(__A);
}
+/// Counts the number of bits in the source operand having a value of 1.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// long long _popcnt64(unsigned long long A);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c POPCNT instruction or a
+/// a sequence of arithmetic and logic ops to calculate it.
+///
+/// \param A
+/// An unsigned 64-bit integer operand.
+/// \returns A 64-bit integer containing the number of bits with value 1 in the
+/// source operand.
+/// \see __popcntq
#define _popcnt64(A) __popcntq((A))
#endif /* __x86_64__ */
@@ -396,6 +481,7 @@ __crc32q(unsigned long long __C, unsigned long long __D)
/// \param __A
/// The performance counter to read.
/// \returns The 64-bit value read from the performance counter.
+/// \see _rdpmc
static __inline__ unsigned long long __DEFAULT_FN_ATTRS
__rdpmc(int __A) {
return __builtin_ia32_rdpmc(__A);
@@ -416,8 +502,35 @@ __rdtscp(unsigned int *__A) {
return __builtin_ia32_rdtscp(__A);
}
+/// Reads the processor's time stamp counter.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned long long _rdtsc();
+/// \endcode
+///
+/// This intrinsic corresponds to the \c RDTSC instruction.
+///
+/// \returns The 64-bit value of the time stamp counter.
#define _rdtsc() __rdtsc()
+/// Reads the specified performance monitoring counter. Refer to your
+/// processor's documentation to determine which performance counters are
+/// supported.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned long long _rdpmc(int A);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c RDPMC instruction.
+///
+/// \param A
+/// The performance counter to read.
+/// \returns The 64-bit value read from the performance counter.
+/// \see __rdpmc
#define _rdpmc(A) __rdpmc(A)
static __inline__ void __DEFAULT_FN_ATTRS
@@ -474,6 +587,7 @@ __rorb(unsigned char __X, int __C) {
/// \param __C
/// The number of bits to rotate the value.
/// \returns The rotated value.
+/// \see _rotwl
static __inline__ unsigned short __DEFAULT_FN_ATTRS_CONSTEXPR
__rolw(unsigned short __X, int __C) {
return __builtin_rotateleft16(__X, __C);
@@ -492,6 +606,7 @@ __rolw(unsigned short __X, int __C) {
/// \param __C
/// The number of bits to rotate the value.
/// \returns The rotated value.
+/// \see _rotwr
static __inline__ unsigned short __DEFAULT_FN_ATTRS_CONSTEXPR
__rorw(unsigned short __X, int __C) {
return __builtin_rotateright16(__X, __C);
@@ -510,6 +625,7 @@ __rorw(unsigned short __X, int __C) {
/// \param __C
/// The number of bits to rotate the value.
/// \returns The rotated value.
+/// \see _rotl
static __inline__ unsigned int __DEFAULT_FN_ATTRS_CONSTEXPR
__rold(unsigned int __X, int __C) {
return __builtin_rotateleft32(__X, (unsigned int)__C);
@@ -528,6 +644,7 @@ __rold(unsigned int __X, int __C) {
/// \param __C
/// The number of bits to rotate the value.
/// \returns The rotated value.
+/// \see _rotr
static __inline__ unsigned int __DEFAULT_FN_ATTRS_CONSTEXPR
__rord(unsigned int __X, int __C) {
return __builtin_rotateright32(__X, (unsigned int)__C);
@@ -575,18 +692,167 @@ __rorq(unsigned long long __X, int __C) {
/* These are already provided as builtins for MSVC. */
/* Select the correct function based on the size of long. */
#ifdef __LP64__
+/// Rotates a 64-bit value to the left by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned long long _lrotl(unsigned long long a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROL instruction.
+///
+/// \param a
+/// The unsigned 64-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rolq
#define _lrotl(a,b) __rolq((a), (b))
+
+/// Rotates a 64-bit value to the right by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned long long _lrotr(unsigned long long a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROR instruction.
+///
+/// \param a
+/// The unsigned 64-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rorq
#define _lrotr(a,b) __rorq((a), (b))
-#else
+#else // __LP64__
+/// Rotates a 32-bit value to the left by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned int _lrotl(unsigned int a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROL instruction.
+///
+/// \param a
+/// The unsigned 32-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rold
#define _lrotl(a,b) __rold((a), (b))
+
+/// Rotates a 32-bit value to the right by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned int _lrotr(unsigned int a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROR instruction.
+///
+/// \param a
+/// The unsigned 32-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rord
#define _lrotr(a,b) __rord((a), (b))
-#endif
+#endif // __LP64__
+
+/// Rotates a 32-bit value to the left by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned int _rotl(unsigned int a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROL instruction.
+///
+/// \param a
+/// The unsigned 32-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rold
#define _rotl(a,b) __rold((a), (b))
+
+/// Rotates a 32-bit value to the right by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned int _rotr(unsigned int a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROR instruction.
+///
+/// \param a
+/// The unsigned 32-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rord
#define _rotr(a,b) __rord((a), (b))
#endif // _MSC_VER
/* These are not builtins so need to be provided in all modes. */
+/// Rotates a 16-bit value to the left by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned short _rotwl(unsigned short a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROL instruction.
+///
+/// \param a
+/// The unsigned 16-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rolw
#define _rotwl(a,b) __rolw((a), (b))
+
+/// Rotates a 16-bit value to the right by the specified number of bits.
+/// This operation is undefined if the number of bits exceeds the size of
+/// the value.
+///
+/// \headerfile <x86intrin.h>
+///
+/// \code
+/// unsigned short _rotwr(unsigned short a, int b);
+/// \endcode
+///
+/// This intrinsic corresponds to the \c ROR instruction.
+///
+/// \param a
+/// The unsigned 16-bit value to be rotated.
+/// \param b
+/// The number of bits to rotate the value.
+/// \returns The rotated value.
+/// \see __rorw
#define _rotwr(a,b) __rorw((a), (b))
#undef __DEFAULT_FN_ATTRS
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