[libc] Add flsll()
Signed-off-by: Michael Brown <mcb30@ipxe.org>
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src/arch/i386/include/bits/strings.h
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src/arch/i386/include/bits/strings.h
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#ifndef _BITS_STRINGS_H
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#define _BITS_STRINGS_H
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FILE_LICENCE ( GPL2_OR_LATER );
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/**
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* Find last (i.e. most significant) set bit
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*
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* @v value Value
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* @ret msb Most significant bit set in value (LSB=1), or zero
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*/
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static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
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long msb_minus_one;
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/* If the input value is zero, the BSR instruction returns
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* ZF=1 and leaves an undefined value in the output register.
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* Perform this check in C rather than asm so that it can be
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* omitted in cases where the compiler is able to prove that
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* the input is non-zero.
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*/
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if ( value ) {
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__asm__ ( "bsrl %1, %0"
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: "=r" ( msb_minus_one )
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: "rm" ( value ) );
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return ( msb_minus_one + 1 );
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} else {
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return 0;
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}
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}
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/**
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* Find last (i.e. most significant) set bit
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*
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* @v value Value
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* @ret msb Most significant bit set in value (LSB=1), or zero
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*/
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static inline __attribute__ (( always_inline )) int __flsll ( long long value ){
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unsigned long high = ( value >> 32 );
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unsigned long low = ( value >> 0 );
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if ( high ) {
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return ( 32 + __flsl ( high ) );
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} else if ( low ) {
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return ( __flsl ( low ) );
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} else {
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return 0;
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}
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}
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#endif /* _BITS_STRINGS_H */
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@ -9,8 +9,8 @@ FILE_LICENCE ( GPL2_OR_LATER );
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* @v value Value
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* @v value Value
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* @ret msb Most significant bit set in value (LSB=1), or zero
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* @ret msb Most significant bit set in value (LSB=1), or zero
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*/
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*/
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static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
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static inline __attribute__ (( always_inline )) int __flsll ( long long value ){
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long msb_minus_one;
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long long msb_minus_one;
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/* If the input value is zero, the BSR instruction returns
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/* If the input value is zero, the BSR instruction returns
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* ZF=1 and leaves an undefined value in the output register.
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* ZF=1 and leaves an undefined value in the output register.
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@ -19,7 +19,7 @@ static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
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* the input is non-zero.
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* the input is non-zero.
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*/
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*/
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if ( value ) {
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if ( value ) {
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__asm__ ( "bsr %1, %0"
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__asm__ ( "bsrq %1, %0"
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: "=r" ( msb_minus_one )
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: "=r" ( msb_minus_one )
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: "rm" ( value ) );
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: "rm" ( value ) );
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return ( msb_minus_one + 1 );
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return ( msb_minus_one + 1 );
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@ -28,4 +28,15 @@ static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
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}
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}
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}
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}
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/**
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* Find last (i.e. most significant) set bit
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*
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* @v value Value
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* @ret msb Most significant bit set in value (LSB=1), or zero
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*/
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static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
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return __flsll ( value );
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}
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#endif /* _BITS_STRINGS_H */
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#endif /* _BITS_STRINGS_H */
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@ -8,15 +8,13 @@ FILE_LICENCE ( GPL2_OR_LATER );
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#include <bits/strings.h>
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#include <bits/strings.h>
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static inline __attribute__ (( always_inline )) int
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static inline __attribute__ (( always_inline )) int
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__constant_flsl ( unsigned long x ) {
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__constant_flsll ( unsigned long long x ) {
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int r = 0;
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int r = 0;
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#if ULONG_MAX > 0xffffffff
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if ( x & 0xffffffff00000000ULL ) {
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if ( x & 0xffffffff00000000UL ) {
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x >>= 32;
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x >>= 32;
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r += 32;
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r += 32;
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}
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}
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#endif
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if ( x & 0xffff0000UL ) {
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if ( x & 0xffff0000UL ) {
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x >>= 16;
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x >>= 16;
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r += 16;
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r += 16;
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@ -43,8 +41,17 @@ __constant_flsl ( unsigned long x ) {
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return r;
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return r;
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}
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}
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static inline __attribute__ (( always_inline )) int
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__constant_flsl ( unsigned long x ) {
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return __constant_flsll ( x );
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}
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int __flsll ( long long x );
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int __flsl ( long x );
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int __flsl ( long x );
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#define flsll( x ) \
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( __builtin_constant_p ( x ) ? __constant_flsll ( x ) : __flsll ( x ) )
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#define flsl( x ) \
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#define flsl( x ) \
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( __builtin_constant_p ( x ) ? __constant_flsl ( x ) : __flsl ( x ) )
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( __builtin_constant_p ( x ) ? __constant_flsl ( x ) : __flsl ( x ) )
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@ -44,6 +44,16 @@ __attribute__ (( noinline )) int flsl_var ( long value ) {
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return flsl ( value );
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return flsl ( value );
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}
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}
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/**
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* Force a call to the non-constant implementation of flsll()
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*
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* @v value Value
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* @ret msb Most significant bit set in value (LSB=1), or zero
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*/
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__attribute__ (( noinline )) int flsll_var ( long long value ) {
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return flsll ( value );
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}
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/**
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/**
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* Check current stack pointer
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* Check current stack pointer
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*
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*
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@ -181,6 +191,25 @@ flsl_okx ( long value, int msb, const char *file, unsigned int line ) {
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}
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}
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#define flsl_ok( value, msb ) flsl_okx ( value, msb, __FILE__, __LINE__ )
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#define flsl_ok( value, msb ) flsl_okx ( value, msb, __FILE__, __LINE__ )
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/**
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* Report a flsll() test result
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*
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* @v value Value
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* @v msb Expected MSB
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* @v file Test code file
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* @v line Test code line
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*/
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static inline __attribute__ (( always_inline )) void
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flsll_okx ( long long value, int msb, const char *file, unsigned int line ) {
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/* Verify as a constant (requires to be inlined) */
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okx ( flsll ( value ) == msb, file, line );
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/* Verify as a non-constant */
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okx ( flsll_var ( value ) == msb, file, line );
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}
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#define flsll_ok( value, msb ) flsll_okx ( value, msb, __FILE__, __LINE__ )
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/**
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/**
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* Report a 64-bit unsigned integer division test result
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* Report a 64-bit unsigned integer division test result
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*
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*
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@ -251,6 +280,14 @@ static void math_test_exec ( void ) {
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flsl_ok ( -1U, ( 8 * sizeof ( int ) ) );
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flsl_ok ( -1U, ( 8 * sizeof ( int ) ) );
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flsl_ok ( -1UL, ( 8 * sizeof ( long ) ) );
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flsl_ok ( -1UL, ( 8 * sizeof ( long ) ) );
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/* Test flsll() */
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flsll_ok ( 0, 0 );
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flsll_ok ( 1, 1 );
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flsll_ok ( 0x6d63623330ULL, 39 );
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flsll_ok ( -1U, ( 8 * sizeof ( int ) ) );
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flsll_ok ( -1UL, ( 8 * sizeof ( long ) ) );
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flsll_ok ( -1ULL, ( 8 * sizeof ( long long ) ) );
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/* Test 64-bit arithmetic
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/* Test 64-bit arithmetic
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*
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*
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* On a 64-bit machine, these tests are fairly meaningless.
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* On a 64-bit machine, these tests are fairly meaningless.
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