Removed REAL_FRAGMENT and REAL_CALL, and left just REAL_EXEC (which is
the only one we actually use). This allows REAL_EXEC fragments to
contain proper references to constraints (e.g. "%w0"), rather than having
to force the use of specific registers.
Note that the "num_constraints" parameter is now completely obsolete, and
that we can probably reduce the syntax to something like
__asm__ __volatile__ ( REAL_CODE ( "asm statements" )
: output constraints
: input constraints
: clobber );
which would look much more natural, and avoid the need to always specify
a clobber list.
Add userptr_t to libkir.h, to allow it to at least compile.
This commit is contained in:
Michael Brown
parent
77a65075a6
commit
3b525385af
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@ -20,10 +20,26 @@
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#define __from_data16( variable ) variable
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#define __from_text16( variable ) variable
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/* Real-mode data and code segments */
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static inline __attribute__ (( always_inline )) unsigned int _rm_cs ( void ) {
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uint16_t cs;
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__asm__ __volatile__ ( "movw %%cs, %w0" : "=r" ( cs ) );
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return cs;
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}
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static inline __attribute__ (( always_inline )) unsigned int _rm_ds ( void ) {
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uint16_t ds;
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__asm__ __volatile__ ( "movw %%ds, %w0" : "=r" ( ds ) );
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return ds;
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}
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#define rm_cs ( _rm_cs() )
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#define rm_ds ( _rm_ds() )
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/* Copy to/from base memory */
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static inline void copy_to_real_libkir ( uint16_t dest_seg, uint16_t dest_off,
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void *src, size_t n ) {
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const void *src, size_t n ) {
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__asm__ __volatile__ ( "movw %4, %%es\n\t"
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"cld\n\t"
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"rep movsb\n\t"
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@ -125,6 +141,69 @@ static inline void copy_from_real_libkir ( void *dest,
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#define put_real put_real_kir
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#define get_real get_real_kir
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/**
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* A pointer to a user buffer
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*
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* This is actually a struct segoff, but encoded as a uint32_t to
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* ensure that gcc passes it around efficiently.
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*/
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typedef uint32_t userptr_t;
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/**
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* Copy data to user buffer
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*
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* @v buffer User buffer
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* @v offset Offset within user buffer
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* @v src Source
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* @v len Length
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*/
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static inline __attribute__ (( always_inline )) void
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copy_to_user ( userptr_t buffer, off_t offset, const void *src, size_t len ) {
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copy_to_real ( ( buffer >> 16 ), ( ( buffer & 0xffff ) + offset ),
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src, len );
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}
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/**
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* Copy data from user buffer
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*
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* @v dest Destination
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* @v buffer User buffer
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* @v offset Offset within user buffer
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* @v len Length
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*/
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static inline __attribute__ (( always_inline )) void
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copy_from_user ( void *dest, userptr_t buffer, off_t offset, size_t len ) {
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copy_from_real ( dest, ( buffer >> 16 ),
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( ( buffer & 0xffff ) + offset ), len );
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}
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/**
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* Convert segment:offset address to user buffer
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*
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* @v segment Real-mode segment
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* @v offset Real-mode offset
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* @ret buffer User buffer
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*/
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static inline __attribute__ (( always_inline )) userptr_t
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real_to_user ( unsigned int segment, unsigned int offset ) {
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return ( ( segment << 16 ) | offset );
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}
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/**
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* Convert virtual address to user buffer
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*
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* @v virtual Virtual address
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* @ret buffer User buffer
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*
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* This constructs a user buffer from an ordinary pointer. Use it
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* when you need to pass a pointer to an internal buffer to a function
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* that expects a @c userptr_t.
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*/
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static inline __attribute__ (( always_inline )) userptr_t
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virt_to_user ( void * virtual ) {
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return real_to_user ( rm_ds, ( intptr_t ) virtual );
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}
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/* Place/remove parameter on real-mode stack in a way that's
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* compatible with libkir
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*/
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@ -134,72 +213,12 @@ static inline void copy_from_real_libkir ( void *dest,
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#define BASEMEM_PARAMETER_INIT BASEMEM_PARAMETER_INIT_LIBKIR
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#define BASEMEM_PARAMETER_DONE BASEMEM_PARAMETER_DONE_LIBKIR
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/* REAL_FRAGMENT: Declare and define a real-mode code fragment in
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* .text16. We don't need this for REAL_EXEC, since we can just
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* execute our real-mode code inline, but it's handy in case someone
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* genuinely wants to create a block of code that can be copied to a
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* specific location and then executed.
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*
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* Note that we put the code in the data segment, since otherwise we
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* can't (easily) access it in order to copy it to its target
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* location. We should never be calling any REAL_FRAGMENT routines
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* directly anyway.
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*/
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#define REAL_FRAGMENT( name, asm_code_str ) \
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extern void name ( void ); \
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extern char name ## _size[]; \
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__asm__ __volatile__ ( \
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".section \".data.text16\"\n\t" \
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".code16\n\t" \
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".arch i386\n\t" \
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#name ":\n\t" \
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asm_code_str "\n\t" \
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"lret\n\t" \
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#name "_end:\n\t" \
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".equ " #name "_size, " #name "_end - " #name "\n\t" \
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".code16gcc\n\t" \
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".previous\n\t" \
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: : \
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)
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#define FRAGMENT_SIZE( fragment ) ( (size_t) fragment ## _size )
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/* REAL_CALL: call an external real-mode routine */
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#define OUT_CONSTRAINTS(...) __VA_ARGS__
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#define IN_CONSTRAINTS(...) "m" ( __routine ), ## __VA_ARGS__
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#define CLOBBER(...) __VA_ARGS__
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#define REAL_CALL( routine, num_out_constraints, out_constraints, \
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in_constraints, clobber ) \
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do { \
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segoff_t __routine = routine; \
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__asm__ __volatile__ ( \
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"pushl %" #num_out_constraints "\n\t" \
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".code16\n\t" \
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"pushw %%gs\n\t" /* preserve segs */ \
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"pushw %%fs\n\t" \
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"pushw %%es\n\t" \
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"pushw %%ds\n\t" \
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"pushw %%cs\n\t" /* lcall to routine */ \
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"call 1f\n\t" \
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"jmp 2f\n\t" \
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"\n1:\n\t" \
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"addr32 pushl 12(%%esp)\n\t" \
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"lret\n\t" \
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"\n2:\n\t" \
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"popw %%ds\n\t" /* restore segs */ \
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"popw %%es\n\t" \
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"popw %%fs\n\t" \
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"popw %%gs\n\t" \
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"addw $4, %%sp\n\t" \
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".code16gcc\n\t" \
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: out_constraints : in_constraints : clobber \
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); \
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} while ( 0 )
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/* REAL_EXEC: execute some inline assembly code in a way that matches
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* the interface of librm
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*/
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#define IN_CONSTRAINTS_NO_ROUTINE( routine, ... ) __VA_ARGS__
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#define OUT_CONSTRAINTS(...) __VA_ARGS__
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#define IN_CONSTRAINTS(...) __VA_ARGS__
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#define CLOBBER(...) __VA_ARGS__
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#define REAL_EXEC( name, asm_code_str, num_out_constraints, out_constraints, \
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in_constraints, clobber ) \
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__asm__ __volatile__ ( \
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@ -216,7 +235,7 @@ static inline void copy_from_real_libkir ( void *dest,
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"popw %%gs\n\t" \
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".code16gcc\n\t" \
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: out_constraints \
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: IN_CONSTRAINTS_NO_ROUTINE ( in_constraints ) \
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: in_constraints \
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: clobber \
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);
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@ -177,9 +177,12 @@ extern void remove_from_rm_stack ( void *data, size_t size );
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#define BASEMEM_PARAMETER_INIT BASEMEM_PARAMETER_INIT_LIBRM
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#define BASEMEM_PARAMETER_DONE BASEMEM_PARAMETER_DONE_LIBRM
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/* REAL_FRAGMENT: Declare and define a real-mode code fragment in .text16 */
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#define REAL_FRAGMENT( name, asm_code_str ) \
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extern void name ( void ); \
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/* REAL_EXEC: execute a fragment of code in real mode */
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#define OUT_CONSTRAINTS(...) __VA_ARGS__
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#define IN_CONSTRAINTS(...) __VA_ARGS__
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#define CLOBBER(...) __VA_ARGS__
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#define REAL_EXEC( name, asm_code_str, num_out_constraints, \
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out_constraints, in_constraints, clobber ) do { \
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__asm__ __volatile__ ( \
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".section \".text16\", \"ax\", @progbits\n\t" \
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".code16\n\t" \
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@ -190,38 +193,10 @@ extern void remove_from_rm_stack ( void *data, size_t size );
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".size " #name ", . - " #name "\n\t" \
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".code32\n\t" \
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".previous\n\t" \
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: : \
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)
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#define FRAGMENT_SIZE( fragment ) ( (size_t) fragment ## _size )
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/* REAL_CALL: call a real-mode routine via librm */
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#define OUT_CONSTRAINTS(...) __VA_ARGS__
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#define IN_CONSTRAINTS(...) __VA_ARGS__
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#define CLOBBER(...) __VA_ARGS__
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#define REAL_CALL( routine, num_out_constraints, out_constraints, \
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in_constraints, clobber ) \
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do { \
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__asm__ __volatile__ ( \
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"pushl $" #routine "\n\t" \
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"call real_call\n\t" \
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"addl $4, %%esp\n\t" \
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: out_constraints \
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: in_constraints \
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: clobber \
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); \
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} while ( 0 )
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/* REAL_EXEC: combine RM_FRAGMENT and REAL_CALL into one handy unit */
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#define PASSTHRU(...) __VA_ARGS__
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#define REAL_EXEC( name, asm_code_str, num_out_constraints, out_constraints, \
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in_constraints, clobber ) \
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do { \
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REAL_FRAGMENT ( name, asm_code_str ); \
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\
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REAL_CALL ( name, num_out_constraints, \
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PASSTHRU ( out_constraints ), \
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PASSTHRU ( in_constraints ), \
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PASSTHRU ( clobber ) ); \
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"pushl $" #name "\n\t" \
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"call real_call\n\t" \
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"addl $4, %%esp\n\t" \
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: out_constraints : in_constraints : clobber ); \
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} while ( 0 )
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#endif /* ASSEMBLY */
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