prog_instruction.h

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

   MAX_OPCODE
} gl_inst_opcode;


/**
 * Instruction source register.
 */
struct prog_src_register
{
   GLuint File:4;	/**< One of the PROGRAM_* register file values. */
   GLint Index:9;	/**< May be negative for relative addressing. */
   GLuint Swizzle:12;
   GLuint RelAddr:1;

   /**
    * \name Source register "sign" control.
    *
    * The ARB and NV extensions allow varrying degrees of control over the
    * sign of the source vector components.  These values allow enough control
    * for all flavors of the extensions.
    */
   /*@{*/
   /**
    * Per-component negation for the SWZ instruction.  For non-SWZ
    * instructions the only possible values are NEGATE_XYZW and NEGATE_NONE.
    *
    * \since
    * ARB_vertex_program, ARB_fragment_program
    */
   GLuint NegateBase:4;

   /**
    * Take the component-wise absolute value.
    *
    * \since
    * NV_fragment_program, NV_fragment_program_option, NV_vertex_program2,
    * NV_vertex_program2_option.
    */
   GLuint Abs:1;

   /**
    * Post-absolute value negation (all components).
    */
   GLuint NegateAbs:1;
   /*@}*/
};


/**
 * Instruction destination register.
 */
struct prog_dst_register
{
   /**
    * One of the PROGRAM_* register file values.
    */
   GLuint File:4;

   GLuint Index:8;
   GLuint WriteMask:4;

   /**
    * \name Conditional destination update control.
    *
    * \since
    * NV_fragment_program, NV_fragment_program_option, NV_vertex_program2,
    * NV_vertex_program2_option.
    */
   /*@{*/
   /**
    * Takes one of the 9 possible condition values (EQ, FL, GT, GE, LE, LT,
    * NE, TR, or UN).  Dest reg is only written to if the matching
    * (swizzled) condition code value passes.  When a conditional update mask
    * is not specified, this will be \c COND_TR.
    */
   GLuint CondMask:4;

   /**
    * Condition code swizzle value.
    */
   GLuint CondSwizzle:12;
   
   /**
    * Selects the condition code register to use for conditional destination
    * update masking.  In NV_fragmnet_program or NV_vertex_program2 mode, only
    * condition code register 0 is available.  In NV_vertex_program3 mode, 
    * condition code registers 0 and 1 are available.
    */
   GLuint CondSrc:1;
   /*@}*/

   GLuint pad:31;
};


/**
 * Vertex/fragment program instruction.
 */
struct prog_instruction
{
   gl_inst_opcode Opcode;
#if FEATURE_MESA_program_debug
   GLshort StringPos;
#endif
   /**
    * Arbitrary data.  Used for the PRINT, CAL, and BRA instructions.
    */
   void *Data;

   struct prog_src_register SrcReg[3];
   struct prog_dst_register DstReg;

   /**
    * Indicates that the instruction should update the condition code
    * register.
    *
    * \since
    * NV_fragment_program, NV_fragment_program_option, NV_vertex_program2,
    * NV_vertex_program2_option.
    */
   GLuint CondUpdate:1;

   /**
    * If prog_instruction::CondUpdate is \c GL_TRUE, this value selects the
    * condition code register that is to be updated.
    *
    * In GL_NV_fragment_program or GL_NV_vertex_program2 mode, only condition
    * code register 0 is available.  In GL_NV_vertex_program3 mode, condition
    * code registers 0 and 1 are available.
    *
    * \since
    * NV_fragment_program, NV_fragment_program_option, NV_vertex_program2,
    * NV_vertex_program2_option.
    */
   GLuint CondDst:1;

   /**
    * Saturate each value of the vectored result to the range [0,1] or the
    * range [-1,1].  \c SSAT mode (i.e., saturation to the range [-1,1]) is
    * only available in NV_fragment_program2 mode.
    * Value is one of the SATURATE_* tokens.
    *
    * \since
    * NV_fragment_program, NV_fragment_program_option, NV_vertex_program3.
    */
   GLuint SaturateMode:2;
   
   /**
    * Per-instruction selectable precision.
    *
    * \since
    * NV_fragment_program, NV_fragment_program_option.
    */
   GLuint Precision:3;

   /**
    * \name Texture source controls.
    * 
    * The texture source controls are only used with the \c TEX, \c TXD,
    * \c TXL, and \c TXP instructions.
    *
    * \since
    * ARB_fragment_program, NV_fragment_program, NV_vertex_program3.
    */
   /*@{*/
   /**
    * Source texture unit.  OpenGL supports a maximum of 32 texture
    * units.
    */
   GLuint TexSrcUnit:5;
   
   /**
    * Source texture target, one of TEXTURE_{1D,2D,3D,CUBE,RECT}_INDEX.
    */
   GLuint TexSrcTarget:3;
   /*@}*/

   /**
    * For BRA and CAL instructions, the location to jump to.
    * For BGNLOOP, points to ENDLOOP (and vice-versa).
    * For BRK, points to BGNLOOP (which points to ENDLOOP).
    * For IF, points to else or endif.
    * For ELSE, points to endif.
    */
   GLint BranchTarget;

   /**
    * For TEX instructions in shaders, the sampler to use for the
    * texture lookup.
    */
   GLint Sampler;

   const char *Comment;
};


extern void
_mesa_init_instructions(struct prog_instruction *inst, GLuint count);

extern struct prog_instruction *
_mesa_alloc_instructions(GLuint numInst);

extern struct prog_instruction *
_mesa_realloc_instructions(struct prog_instruction *oldInst,
                           GLuint numOldInst, GLuint numNewInst);

extern struct prog_instruction *
_mesa_copy_instructions(struct prog_instruction *dest,
                        const struct prog_instruction *src, GLuint n);

extern void
_mesa_free_instructions(struct prog_instruction *inst, GLuint count);

extern GLuint
_mesa_num_inst_src_regs(gl_inst_opcode opcode);

extern GLuint
_mesa_num_inst_dst_regs(gl_inst_opcode opcode);

extern GLboolean
_mesa_is_tex_instruction(gl_inst_opcode opcode);

extern const char *
_mesa_opcode_string(gl_inst_opcode opcode);


#endif /* PROG_INSTRUCTION_H */