path: root/src/mesa/shader/nvvertexec.c

/*
 * Mesa 3-D graphics library
 * Version:  6.5.2
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file nvvertexec.c
 * Code to execute vertex programs.
 * \author Brian Paul
 */

#include "glheader.h"
#include "context.h"
#include "imports.h"
#include "macros.h"
#include "nvvertexec.h"
#include "prog_parameter.h"
#include "prog_statevars.h"
#include "prog_instruction.h"
#include "math/m_matrix.h"


static const GLboolean DEBUG_VERT = GL_FALSE;

static const GLfloat ZeroVec[4] = { 0.0F, 0.0F, 0.0F, 0.0F };


/**
 * Load/initialize the vertex program registers which need to be set
 * per-vertex.
 */
void
_mesa_init_vp_per_vertex_registers(GLcontext *ctx, struct vp_machine *machine)
{
   /* Input registers get initialized from the current vertex attribs */
   MEMCPY(machine->Inputs, ctx->Current.Attrib,
          MAX_VERTEX_PROGRAM_ATTRIBS * 4 * sizeof(GLfloat));

   if (ctx->VertexProgram.Current->IsNVProgram) {
      GLuint i;
      /* Output/result regs are initialized to [0,0,0,1] */
      for (i = 0; i < MAX_NV_VERTEX_PROGRAM_OUTPUTS; i++) {
         ASSIGN_4V(machine->Outputs[i], 0.0F, 0.0F, 0.0F, 1.0F);
      }
      /* Temp regs are initialized to [0,0,0,0] */
      for (i = 0; i < MAX_NV_VERTEX_PROGRAM_TEMPS; i++) {
         ASSIGN_4V(machine->Temporaries[i], 0.0F, 0.0F, 0.0F, 0.0F);
      }
      for (i = 0; i < MAX_VERTEX_PROGRAM_ADDRESS_REGS; i++) {
         ASSIGN_4V(machine->AddressReg[i], 0, 0, 0, 0);
      }
   }

   /* init condition codes */
   machine->CondCodes[0] = COND_EQ;
   machine->CondCodes[1] = COND_EQ;
   machine->CondCodes[2] = COND_EQ;
   machine->CondCodes[3] = COND_EQ;
}



/**
 * Copy the 16 elements of a matrix into four consecutive program
 * registers starting at 'pos'.
 */
static void
load_matrix(GLfloat registers[][4], GLuint pos, const GLfloat mat[16])
{
   GLuint i;
   for (i = 0; i < 4; i++) {
      registers[pos + i][0] = mat[0 + i];
      registers[pos + i][1] = mat[4 + i];
      registers[pos + i][2] = mat[8 + i];
      registers[pos + i][3] = mat[12 + i];
   }
}


/**
 * As above, but transpose the matrix.
 */
static void
load_transpose_matrix(GLfloat registers[][4], GLuint pos,
                      const GLfloat mat[16])
{
   MEMCPY(registers[pos], mat, 16 * sizeof(GLfloat));
}


/**
 * Load program parameter registers with tracked matrices (if NV program)
 * or GL state values (if ARB program).
 * This needs to be done per glBegin/glEnd, not per-vertex.
 */
void
_mesa_init_vp_per_primitive_registers(GLcontext *ctx)
{
   if (ctx->VertexProgram.Current->IsNVProgram) {
      GLuint i;

      for (i = 0; i < MAX_NV_VERTEX_PROGRAM_PARAMS / 4; i++) {
         /* point 'mat' at source matrix */
         GLmatrix *mat;
         if (ctx->VertexProgram.TrackMatrix[i] == GL_MODELVIEW) {
            mat = ctx->ModelviewMatrixStack.Top;
         }
         else if (ctx->VertexProgram.TrackMatrix[i] == GL_PROJECTION) {
            mat = ctx->ProjectionMatrixStack.Top;
         }
         else if (ctx->VertexProgram.TrackMatrix[i] == GL_TEXTURE) {
            mat = ctx->TextureMatrixStack[ctx->Texture.CurrentUnit].Top;
         }
         else if (ctx->VertexProgram.TrackMatrix[i] == GL_COLOR) {
            mat = ctx->ColorMatrixStack.Top;
         }
         else if (ctx->VertexProgram.TrackMatrix[i]==GL_MODELVIEW_PROJECTION_NV) {
            /* XXX verify the combined matrix is up to date */
            mat = &ctx->_ModelProjectMatrix;
         }
         else if (ctx->VertexProgram.TrackMatrix[i] >= GL_MATRIX0_NV &&
                  ctx->VertexProgram.TrackMatrix[i] <= GL_MATRIX7_NV) {
            GLuint n = ctx->VertexProgram.TrackMatrix[i] - GL_MATRIX0_NV;
            ASSERT(n < MAX_PROGRAM_MATRICES);
            mat = ctx->ProgramMatrixStack[n].Top;
         }
         else {
            /* no matrix is tracked, but we leave the register values as-is */
            assert(ctx->VertexProgram.TrackMatrix[i] == GL_NONE);
            continue;
         }

         /* load the matrix values into sequential registers */
         if (ctx->VertexProgram.TrackMatrixTransform[i] == GL_IDENTITY_NV) {
            load_matrix(ctx->VertexProgram.Parameters, i*4, mat->m);
         }
         else if (ctx->VertexProgram.TrackMatrixTransform[i] == GL_INVERSE_NV) {
            _math_matrix_analyse(mat); /* update the inverse */
            ASSERT(!_math_matrix_is_dirty(mat));
            load_matrix(ctx->VertexProgram.Parameters, i*4, mat->inv);
         }
         else if (ctx->VertexProgram.TrackMatrixTransform[i] == GL_TRANSPOSE_NV) {
            load_transpose_matrix(ctx->VertexProgram.Parameters, i*4, mat->m);
         }
         else {
            assert(ctx->VertexProgram.TrackMatrixTransform[i]
                   == GL_INVERSE_TRANSPOSE_NV);
            _math_matrix_analyse(mat); /* update the inverse */
            ASSERT(!_math_matrix_is_dirty(mat));
            load_transpose_matrix(ctx->VertexProgram.Parameters, i*4, mat->inv);
         }
      }
   }
   else {
      /* ARB vertex program */
      if (ctx->VertexProgram.Current->Base.Parameters) {
         /* Grab the state GL state and put into registers */
         _mesa_load_state_parameters(ctx,
                                 ctx->VertexProgram.Current->Base.Parameters);
      }
   }
}



/**
 * For debugging.  Dump the current vertex program machine registers.
 */
void
_mesa_dump_vp_state( const struct gl_vertex_program_state *state,
                     const struct vp_machine *machine)
{
   int i;
   _mesa_printf("VertexIn:\n");
   for (i = 0; i < MAX_NV_VERTEX_PROGRAM_INPUTS; i++) {
      _mesa_printf("%d: %f %f %f %f   ", i,
                   machine->Inputs[i][0],
                   machine->Inputs[i][1],
                   machine->Inputs[i][2],
                   machine->Inputs[i][3]);
   }
   _mesa_printf("\n");

   _mesa_printf("VertexOut:\n");
   for (i = 0; i < MAX_NV_VERTEX_PROGRAM_OUTPUTS; i++) {
      _mesa_printf("%d: %f %f %f %f   ", i,
                  machine->Outputs[i][0],
                  machine->Outputs[i][1],
                  machine->Outputs[i][2],
                  machine->Outputs[i][3]);
   }
   _mesa_printf("\n");

   _mesa_printf("Registers:\n");
   for (i = 0; i < MAX_PROGRAM_TEMPS; i++) {
      _mesa_printf("%d: %f %f %f %f   ", i,
                  machine->Temporaries[i][0],
                  machine->Temporaries[i][1],
                  machine->Temporaries[i][2],
                  machine->Temporaries[i][3]);
   }
   _mesa_printf("\n");

   _mesa_printf("Parameters:\n");
   for (i = 0; i < MAX_NV_VERTEX_PROGRAM_PARAMS; i++) {
      _mesa_printf("%d: %f %f %f %f   ", i,
                  state->Parameters[i][0],
                  state->Parameters[i][1],
                  state->Parameters[i][2],
                  state->Parameters[i][3]);
   }
   _mesa_printf("\n");
}



/**
 * Return a pointer to the 4-element float vector specified by the given
 * source register.
 */
static INLINE const GLfloat *
get_register_pointer( GLcontext *ctx,
                      const struct prog_src_register *source,
                      struct vp_machine *machine,
                      const struct gl_vertex_program *program )
{
   if (source->RelAddr) {
      const GLint reg = source->Index + machine->AddressReg[0][0];
      ASSERT(source->File == PROGRAM_ENV_PARAM || 
             source->File == PROGRAM_STATE_VAR ||
             source->File == PROGRAM_LOCAL_PARAM);
      if (reg < 0 || reg > MAX_NV_VERTEX_PROGRAM_PARAMS)
         return ZeroVec;
      else if (source->File == PROGRAM_ENV_PARAM)
         return ctx->VertexProgram.Parameters[reg];
      else {
         ASSERT(source->File == PROGRAM_LOCAL_PARAM ||
                source->File == PROGRAM_STATE_VAR);
         return program->Base.Parameters->ParameterValues[reg];
      }
   }
   else {
      switch (source->File) {
         case PROGRAM_TEMPORARY:
            ASSERT(source->Index < MAX_PROGRAM_TEMPS);
            return machine->Temporaries[source->Index];
         case PROGRAM_INPUT:
            ASSERT(source->Index < VERT_ATTRIB_MAX);
            return machine->Inputs[source->Index];
         case PROGRAM_OUTPUT:
            /* This is only needed for the PRINT instruction */
            ASSERT(source->Index < VERT_RESULT_MAX);
            return machine->Outputs[source->Index];
         case PROGRAM_LOCAL_PARAM:
            ASSERT(source->Index < MAX_PROGRAM_LOCAL_PARAMS);
            return program->Base.LocalParams[source->Index];
         case PROGRAM_ENV_PARAM:
            ASSERT(source->Index < MAX_NV_VERTEX_PROGRAM_PARAMS);
            return ctx->VertexProgram.Parameters[source->Index];
         case PROGRAM_STATE_VAR:
            /* Fallthrough */
         case PROGRAM_CONSTANT:
            /* Fallthrough */
         case PROGRAM_UNIFORM:
            /* Fallthrough */
         case PROGRAM_NAMED_PARAM:
            ASSERT(source->Index < program->Base.Parameters->NumParameters);
            return program->Base.Parameters->ParameterValues[source->Index];
         default:
            _mesa_problem(NULL,
                          "Bad source register file in get_register_pointer");
            return NULL;
      }
   }
   return NULL;
}


/**
 * Fetch a 4-element float vector from the given source register.
 * Apply swizzling and negating as needed.
 */
static INLINE void
fetch_vector4( GLcontext *ctx, 
               const struct prog_src_register *source,
               struct vp_machine *machine,
               const struct gl_vertex_program *program,
               GLfloat result[4] )
{
   const GLfloat *src = get_register_pointer(ctx, source, machine, program);
   ASSERT(src);
   result[0] = src[GET_SWZ(source->Swizzle, 0)];
   result[1] = src[GET_SWZ(source->Swizzle, 1)];
   result[2] = src[GET_SWZ(source->Swizzle, 2)];
   result[3] = src[GET_SWZ(source->Swizzle, 3)];
   if (source->NegateBase) {
      result[0] = -result[0];
      result[1] = -result[1];
      result[2] = -result[2];
      result[3] = -result[3];
   }
}



/**
 * As above, but only return result[0] element.
 */
static INLINE void
fetch_vector1( GLcontext *ctx,
               const struct prog_src_register *source,
               struct vp_machine *machine,
               const struct gl_vertex_program *program,
               GLfloat result[4] )
{
   const GLfloat *src = get_register_pointer(ctx, source, machine, program);
   ASSERT(src);
   result[0] = src[GET_SWZ(source->Swizzle, 0)];
   if (source->NegateBase) {
      result[0] = -result[0];
   }
}


/**
 * Test value against zero and return GT, LT, EQ or UN if NaN.
 */
static INLINE GLuint
generate_cc( float value )
{
   if (value != value)
      return COND_UN;  /* NaN */
   if (value > 0.0F)
      return COND_GT;
   if (value < 0.0F)
      return COND_LT;
   return COND_EQ;
}


/**
 * Test if the ccMaskRule is satisfied by the given condition code.
 * Used to mask destination writes according to the current condition code.
 */
static INLINE GLboolean
test_cc(GLuint condCode, GLuint ccMaskRule)
{
   switch (ccMaskRule) {
   case COND_EQ: return (condCode == COND_EQ);
   case COND_NE: return (condCode != COND_EQ);
   case COND_LT: return (condCode == COND_LT);
   case COND_GE: return (condCode == COND_GT || condCode == COND_EQ);
   case COND_LE: return (condCode == COND_LT || condCode == COND_EQ);
   case COND_GT: return (condCode == COND_GT);
   case COND_TR: return GL_TRUE;
   case COND_FL: return GL_FALSE;
   default:      return GL_TRUE;
   }
}


/**
 * Evaluate the 4 condition codes against a predicate and return GL_TRUE
 * or GL_FALSE to indicate result.
 */
static INLINE GLboolean
eval_condition(const struct vp_machine *machine,
               const struct prog_instruction *inst)
{
   const GLuint swizzle = inst->DstReg.CondSwizzle;
   const GLuint condMask = inst->DstReg.CondMask;
   if (test_cc(machine->CondCodes[GET_SWZ(swizzle, 0)], condMask) ||
       test_cc(machine->CondCodes[GET_SWZ(swizzle, 1)], condMask) ||
       test_cc(machine->CondCodes[GET_SWZ(swizzle, 2)], condMask) ||
       test_cc(machine->CondCodes[GET_SWZ(swizzle, 3)], condMask)) {
      return GL_TRUE;
   }
   else {
      return GL_FALSE;
   }
}


/**
 * Store 4 floats into a register.
 */
static void
store_vector4( const struct prog_instruction *inst,
               struct vp_machine *machine,
               const GLfloat value[4] )
{
   const struct prog_dst_register *dest = &(inst->DstReg);
   GLuint writeMask = dest->WriteMask;
   GLfloat *dst;

   switch (dest->File) {
      case PROGRAM_OUTPUT:
         ASSERT(dest->Index < VERT_RESULT_MAX);
         dst = machine->Outputs[dest->Index];
         break;
      case PROGRAM_TEMPORARY:
         ASSERT(dest->Index < MAX_PROGRAM_TEMPS);
         dst = machine->Temporaries[dest->Index];
         break;
      case PROGRAM_ENV_PARAM:
         /* Only for VP state programs */
         {
            /* a slight hack */
            GET_CURRENT_CONTEXT(ctx);
            ASSERT(dest->Index < MAX_PROGRAM_ENV_PARAMS);
            dst = ctx->VertexProgram.Parameters[dest->Index];
         }
         break;
      default:
         _mesa_problem(NULL, "Invalid register file in store_vector4(file=%d)",
                       dest->File);
         return;
   }

   if (dest->WriteMask & WRITEMASK_X)
      dst[0] = value[0];
   if (dest->WriteMask & WRITEMASK_Y)
      dst[1] = value[1];
   if (dest->WriteMask & WRITEMASK_Z)
      dst[2] = value[2];
   if (dest->WriteMask & WRITEMASK_W)
      dst[3] = value[3];

   if (inst->CondUpdate) {
      if (writeMask & WRITEMASK_X)
         machine->CondCodes[0] = generate_cc(value[0]);
      if (writeMask & WRITEMASK_Y)
         machine->CondCodes[1] = generate_cc(value[1]);
      if (writeMask & WRITEMASK_Z)
         machine->CondCodes[2] = generate_cc(value[2]);
      if (writeMask & WRITEMASK_W)
         machine->CondCodes[3] = generate_cc(value[3]);
   }
}


/**
 * Set x to positive or negative infinity.
 */
#if defined(USE_IEEE) || defined(_WIN32)
#define SET_POS_INFINITY(x)  ( *((GLuint *) (void *)&x) = 0x7F800000 )
#define SET_NEG_INFINITY(x)  ( *((GLuint *) (void *)&x) = 0xFF800000 )
#elif defined(VMS)
#define SET_POS_INFINITY(x)  x = __MAXFLOAT
#define SET_NEG_INFINITY(x)  x = -__MAXFLOAT
#else
#define SET_POS_INFINITY(x)  x = (GLfloat) HUGE_VAL
#define SET_NEG_INFINITY(x)  x = (GLfloat) -HUGE_VAL
#endif

#define SET_FLOAT_BITS(x, bits) ((fi_type *) (void *) &(x))->i = bits


/**
 * Execute the given vertex program
 */
void
_mesa_exec_vertex_program(GLcontext *ctx,
                          struct vp_machine *machine,
                          const struct gl_vertex_program *program)
{
   const GLuint maxInst = program->Base.NumInstructions;
   GLuint pc;

   ctx->_CurrentProgram = GL_VERTEX_PROGRAM_ARB; /* or NV, doesn't matter */

   /* If the program is position invariant, multiply the input position
    * by the MVP matrix and store in the vertex position result register.
    */
   if (ctx->VertexProgram.Current->IsPositionInvariant) {
      TRANSFORM_POINT( machine->Outputs[VERT_RESULT_HPOS], 
                       ctx->_ModelProjectMatrix.m, 
                       machine->Inputs[VERT_ATTRIB_POS]);

      /* XXX: This could go elsewhere */
      ctx->VertexProgram.Current->Base.OutputsWritten |= VERT_BIT_POS;
   }

   for (pc = 0; pc < maxInst; pc++) {
      const struct prog_instruction *inst = program->Base.Instructions + pc;

      if (ctx->VertexProgram.CallbackEnabled &&
          ctx->VertexProgram.Callback) {
         ctx->VertexProgram.CurrentPosition = inst->StringPos;
         ctx->VertexProgram.Callback(program->Base.Target,
                                     ctx->VertexProgram.CallbackData);
      }

      switch (inst->Opcode) {
      case OPCODE_ABS: /* GL_NV_vertex_program1_1 */
         {
            GLfloat t[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            if (t[0] < 0.0)  t[0] = -t[0];
            if (t[1] < 0.0)  t[1] = -t[1];
            if (t[2] < 0.0)  t[2] = -t[2];
            if (t[3] < 0.0)  t[3] = -t[3];
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_ADD:
         {
            GLfloat t[4], u[4], sum[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            sum[0] = t[0] + u[0];
            sum[1] = t[1] + u[1];
            sum[2] = t[2] + u[2];
            sum[3] = t[3] + u[3];
            store_vector4( inst, machine, sum );
         }
         break;
      case OPCODE_ARA:
         break;
      case OPCODE_ARL:
         {
            GLfloat t[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            machine->AddressReg[0][0] = (GLint) FLOORF(t[0]);
         }
         break;
      case OPCODE_ARL_NV:
         break;
      case OPCODE_ARR:
         break;
      case OPCODE_BGNLOOP:
         /* no-op */
         break;
      case OPCODE_ENDLOOP:
         /* subtract 1 here since pc is incremented by for(pc) loop */
         pc = inst->BranchTarget - 1; /* go to matching BNGLOOP */
         break;
      case OPCODE_BRA: /* branch (conditional) */
         /* fall-through */
      case OPCODE_BRK: /* break out of loop (conditional) */
         /* fall-through */
      case OPCODE_CONT: /* continue loop (conditional) */
         if (eval_condition(machine, inst)) {
            /* take branch */
            /* Subtract 1 here since we'll do pc++ at end of for-loop */
            pc = inst->BranchTarget - 1;
         }
         break;
      case OPCODE_CAL: /* Call subroutine (conditional) */
         if (eval_condition(machine, inst)) {
            /* call the subroutine */
            if (machine->StackDepth >= MAX_PROGRAM_CALL_DEPTH) {
               return; /* abort execution */
            }
            machine->CallStack[machine->StackDepth++] = pc + 1;
            pc = inst->BranchTarget; /* XXX - 1 ??? */
         }
         break;
      case OPCODE_CMP:
         {
            GLfloat a[4], b[4], c[4], result[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, a );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, b );
            fetch_vector4( ctx, &inst->SrcReg[2], machine, program, c );
            result[0] = a[0] < 0.0F ? b[0] : c[0];
            result[1] = a[1] < 0.0F ? b[1] : c[1];
            result[2] = a[2] < 0.0F ? b[2] : c[2];
            result[3] = a[3] < 0.0F ? b[3] : c[3];
            store_vector4( inst, machine, result );
         }
         break;
      case OPCODE_COS:
         {
            GLfloat a[4], result[4];
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, a );
            result[0] = result[1] = result[2] = result[3]
               = (GLfloat) _mesa_cos(a[0]);
            store_vector4( inst, machine, result );
         }
         break;
      case OPCODE_DDX:
         /* fallthrough */
      case OPCODE_DDY:
         _mesa_problem(ctx, "DDX/DDY not allowed in vertex programs");
         break;

      case OPCODE_DP3:
         {
            GLfloat t[4], u[4], dot[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            dot[0] = t[0] * u[0] + t[1] * u[1] + t[2] * u[2];
            dot[1] = dot[2] = dot[3] = dot[0];
            store_vector4( inst, machine, dot );
         }
         break;
      case OPCODE_DP4:
         {
            GLfloat t[4], u[4], dot[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            dot[0] = t[0] * u[0] + t[1] * u[1] + t[2] * u[2] + t[3] * u[3];
            dot[1] = dot[2] = dot[3] = dot[0];
            store_vector4( inst, machine, dot );
         }
         break;
      case OPCODE_DPH:
         {
            GLfloat t[4], u[4], dot[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            dot[0] = t[0] * u[0] + t[1] * u[1] + t[2] * u[2] + u[3];
            dot[1] = dot[2] = dot[3] = dot[0];
            store_vector4( inst, machine, dot );
         }
         break;
      case OPCODE_DST:
         {
            GLfloat t[4], u[4], dst[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            dst[0] = 1.0F;
            dst[1] = t[1] * u[1];
            dst[2] = t[2];
            dst[3] = u[3];
            store_vector4( inst, machine, dst );
         }
         break;
      case OPCODE_EXP:
         {
            GLfloat t[4], q[4], floor_t0;
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            floor_t0 = FLOORF(t[0]);
            if (floor_t0 > FLT_MAX_EXP) {
               SET_POS_INFINITY(q[0]);
               SET_POS_INFINITY(q[2]);
            }
            else if (floor_t0 < FLT_MIN_EXP) {
               q[0] = 0.0F;
               q[2] = 0.0F;
            }
            else {
#ifdef USE_IEEE
               GLint ii = (GLint) floor_t0;
               ii = (ii < 23) + 0x3f800000;
               SET_FLOAT_BITS(q[0], ii);
               q[0] = *((GLfloat *) (void *)&ii);
#else
               q[0] = (GLfloat) pow(2.0, floor_t0);
#endif
               q[2] = (GLfloat) (q[0] * LOG2(q[1]));
            }
            q[1] = t[0] - floor_t0;
            q[3] = 1.0F;
            store_vector4( inst, machine, q );
         }
         break;
      case OPCODE_EX2: /* GL_ARB_vertex_program */
         {
            GLfloat t[4];
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            t[0] = t[1] = t[2] = t[3] = (GLfloat)_mesa_pow(2.0, t[0]);
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_FLR: /* GL_ARB_vertex_program */
         {
            GLfloat t[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            t[0] = FLOORF(t[0]);
            t[1] = FLOORF(t[1]);
            t[2] = FLOORF(t[2]);
            t[3] = FLOORF(t[3]);
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_FRC: /* GL_ARB_vertex_program */
         {
            GLfloat t[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            t[0] = t[0] - FLOORF(t[0]);
            t[1] = t[1] - FLOORF(t[1]);
            t[2] = t[2] - FLOORF(t[2]);
            t[3] = t[3] - FLOORF(t[3]);
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_IF:
         if (eval_condition(machine, inst)) {
            /* do if-clause (just continue execution) */
         }
         else {
            /* go to the instruction after ELSE or ENDIF */
            assert(inst->BranchTarget >= 0);
            pc = inst->BranchTarget - 1;
         }
         break;
      case OPCODE_ELSE:
         /* goto ENDIF */
         assert(inst->BranchTarget >= 0);
         pc = inst->BranchTarget - 1;
         break;
      case OPCODE_ENDIF:
         /* nothing */
         break;
      case OPCODE_MOV:
         {
            GLfloat t[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_LIT:
         {
            const GLfloat epsilon = 1.0F / 256.0F; /* per NV spec */
            GLfloat t[4], lit[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            t[0] = MAX2(t[0], 0.0F);
            t[1] = MAX2(t[1], 0.0F);
            t[3] = CLAMP(t[3], -(128.0F - epsilon), (128.0F - epsilon));
            lit[0] = 1.0;
            lit[1] = t[0];
            lit[2] = (t[0] > 0.0) ? (GLfloat) _mesa_pow(t[1], t[3]) : 0.0F;
            lit[3] = 1.0;
            store_vector4( inst, machine, lit );
         }
         break;
      case OPCODE_LOG:
         {
            GLfloat t[4], q[4], abs_t0;
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            abs_t0 = FABSF(t[0]);
            if (abs_t0 != 0.0F) {
               /* Since we really can't handle infinite values on VMS
                * like other OSes we'll use __MAXFLOAT to represent
                * infinity.  This may need some tweaking.
                */
#ifdef VMS
               if (abs_t0 == __MAXFLOAT)
#else
               if (IS_INF_OR_NAN(abs_t0))
#endif
               {
                  SET_POS_INFINITY(q[0]);
                  q[1] = 1.0F;
                  SET_POS_INFINITY(q[2]);
               }
               else {
                  int exponent;
                  GLfloat mantissa = FREXPF(t[0], &exponent);
                  q[0] = (GLfloat) (exponent - 1);
                  q[1] = (GLfloat) (2.0 * mantissa); /* map [.5, 1) -> [1, 2) */
                  q[2] = (GLfloat) (q[0] + LOG2(q[1]));
               }
            }
            else {
               SET_NEG_INFINITY(q[0]);
               q[1] = 1.0F;
               SET_NEG_INFINITY(q[2]);
            }
            q[3] = 1.0;
            store_vector4( inst, machine, q );
         }
         break;
      case OPCODE_MAD:
         {
            GLfloat t[4], u[4], v[4], sum[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            fetch_vector4( ctx, &inst->SrcReg[2], machine, program, v );
            sum[0] = t[0] * u[0] + v[0];
            sum[1] = t[1] * u[1] + v[1];
            sum[2] = t[2] * u[2] + v[2];
            sum[3] = t[3] * u[3] + v[3];
            store_vector4( inst, machine, sum );
         }
         break;
      case OPCODE_MAX:
         {
            GLfloat t[4], u[4], max[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            max[0] = (t[0] > u[0]) ? t[0] : u[0];
            max[1] = (t[1] > u[1]) ? t[1] : u[1];
            max[2] = (t[2] > u[2]) ? t[2] : u[2];
            max[3] = (t[3] > u[3]) ? t[3] : u[3];
            store_vector4( inst, machine, max );
         }
         break;
      case OPCODE_MIN:
         {
            GLfloat t[4], u[4], min[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            min[0] = (t[0] < u[0]) ? t[0] : u[0];
            min[1] = (t[1] < u[1]) ? t[1] : u[1];
            min[2] = (t[2] < u[2]) ? t[2] : u[2];
            min[3] = (t[3] < u[3]) ? t[3] : u[3];
            store_vector4( inst, machine, min );
         }
         break;
      case OPCODE_MUL:
         {
            GLfloat t[4], u[4], prod[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            prod[0] = t[0] * u[0];
            prod[1] = t[1] * u[1];
            prod[2] = t[2] * u[2];
            prod[3] = t[3] * u[3];
            store_vector4( inst, machine, prod );
         }
         break;
      case OPCODE_RCP:
         {
            GLfloat t[4];
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            if (t[0] != 1.0F)
               t[0] = 1.0F / t[0];  /* div by zero is infinity! */
            t[1] = t[2] = t[3] = t[0];
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_RSQ:
         {
            GLfloat t[4];
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            t[0] = INV_SQRTF(FABSF(t[0]));
            t[1] = t[2] = t[3] = t[0];
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_SLT:
         {
            GLfloat t[4], u[4], slt[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            slt[0] = (t[0] < u[0]) ? 1.0F : 0.0F;
            slt[1] = (t[1] < u[1]) ? 1.0F : 0.0F;
            slt[2] = (t[2] < u[2]) ? 1.0F : 0.0F;
            slt[3] = (t[3] < u[3]) ? 1.0F : 0.0F;
            store_vector4( inst, machine, slt );
         }
         break;
      case OPCODE_SGE:
         {
            GLfloat t[4], u[4], sge[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            sge[0] = (t[0] >= u[0]) ? 1.0F : 0.0F;
            sge[1] = (t[1] >= u[1]) ? 1.0F : 0.0F;
            sge[2] = (t[2] >= u[2]) ? 1.0F : 0.0F;
            sge[3] = (t[3] >= u[3]) ? 1.0F : 0.0F;
            store_vector4( inst, machine, sge );
         }
         break;
      case OPCODE_SGT: /* set on greater */
         {
            GLfloat a[4], b[4], result[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, a );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, b );
            result[0] = (a[0] > b[0]) ? 1.0F : 0.0F;
            result[1] = (a[1] > b[1]) ? 1.0F : 0.0F;
            result[2] = (a[2] > b[2]) ? 1.0F : 0.0F;
            result[3] = (a[3] > b[3]) ? 1.0F : 0.0F;
            store_vector4( inst, machine, result );
            if (DEBUG_VERT) {
               printf("SGT %g %g %g %g\n",
                      result[0], result[1], result[2], result[3]);
            }
         }
         break;
      case OPCODE_RCC:
         {
            GLfloat t[4], u;
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            if (t[0] == 1.0F)
               u = 1.0F;
            else
               u = 1.0F / t[0];
            if (u > 0.0F) {
               if (u > 1.884467e+019F) {
                  u = 1.884467e+019F;  /* IEEE 32-bit binary value 0x5F800000 */
               }
               else if (u < 5.42101e-020F) {
                  u = 5.42101e-020F;   /* IEEE 32-bit binary value 0x1F800000 */
               }
            }
            else {
               if (u < -1.884467e+019F) {
                  u = -1.884467e+019F; /* IEEE 32-bit binary value 0xDF800000 */
               }
               else if (u > -5.42101e-020F) {
                  u = -5.42101e-020F;  /* IEEE 32-bit binary value 0x9F800000 */
               }
            }
            t[0] = t[1] = t[2] = t[3] = u;
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_SUB: /* GL_NV_vertex_program1_1 */
         {
            GLfloat t[4], u[4], sum[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            sum[0] = t[0] - u[0];
            sum[1] = t[1] - u[1];
            sum[2] = t[2] - u[2];
            sum[3] = t[3] - u[3];
            store_vector4( inst, machine, sum );
         }
         break;
      case OPCODE_LG2: /* GL_ARB_vertex_program */
         {
            GLfloat t[4];
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            t[0] = t[1] = t[2] = t[3] = LOG2(t[0]);
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_POW: /* GL_ARB_vertex_program */
         {
            GLfloat t[4], u[4];
            fetch_vector1( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector1( ctx, &inst->SrcReg[1], machine, program, u );
            t[0] = t[1] = t[2] = t[3] = (GLfloat)_mesa_pow(t[0], u[0]);
            store_vector4( inst, machine, t );
         }
         break;
      case OPCODE_XPD: /* GL_ARB_vertex_program */
         {
            GLfloat t[4], u[4], cross[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            fetch_vector4( ctx, &inst->SrcReg[1], machine, program, u );
            cross[0] = t[1] * u[2] - t[2] * u[1];
            cross[1] = t[2] * u[0] - t[0] * u[2];
            cross[2] = t[0] * u[1] - t[1] * u[0];
            cross[3] = 0.0;
            store_vector4( inst, machine, cross );
         }
         break;
      case OPCODE_SWZ: /* GL_ARB_vertex_program */
         {
            const struct prog_src_register *source = &inst->SrcReg[0];
            const GLfloat *src = get_register_pointer(ctx, source,
                                                      machine, program);
            GLfloat result[4];
            GLuint i;
            
            /* do extended swizzling here */
            for (i = 0; i < 4; i++) {
               const GLuint swz = GET_SWZ(source->Swizzle, i);
               if (swz == SWIZZLE_ZERO)
                  result[i] = 0.0;
               else if (swz == SWIZZLE_ONE)
                  result[i] = 1.0;
               else {
                  ASSERT(swz >= 0);
                  ASSERT(swz <= 3);
                  result[i] = src[swz];
               }
               if (source->NegateBase & (1 << i))
                  result[i] = -result[i];
            }
            store_vector4( inst, machine, result );
         }
         break;
      case OPCODE_PRINT:
         if (inst->SrcReg[0].File) {
            GLfloat t[4];
            fetch_vector4( ctx, &inst->SrcReg[0], machine, program, t );
            _mesa_printf("%s%g, %g, %g, %g\n",
                         (char *) inst->Data, t[0], t[1], t[2], t[3]);
         }
         else {
            _mesa_printf("%s\n", (char *) inst->Data);
         }
         break;
      case OPCODE_END:
         ctx->_CurrentProgram = 0;
         return;
      case OPCODE_NOP:
         break;
      default:
         /* bad instruction opcode */
         _mesa_problem(ctx, "Bad VP Opcode in _mesa_exec_vertex_program");
         ctx->_CurrentProgram = 0;
         return;
      } /* switch */
   } /* for */

   ctx->_CurrentProgram = 0;
}


/**
 * Execute a vertex state program.
 * \sa _mesa_ExecuteProgramNV
 */
void
_mesa_exec_vertex_state_program(GLcontext *ctx,
                                struct gl_vertex_program *vprog,
                                const GLfloat *params)
{
   struct vp_machine machine;
   _mesa_init_vp_per_vertex_registers(ctx, &machine);
   _mesa_init_vp_per_primitive_registers(ctx);
   COPY_4V(machine.Inputs[VERT_ATTRIB_POS], params);
   _mesa_exec_vertex_program(ctx, &machine, vprog);
}