Initial revision
diff --git a/src/mesa/main/depth.c b/src/mesa/main/depth.c
new file mode 100644
index 0000000..6d5a2be
--- /dev/null
+++ b/src/mesa/main/depth.c
@@ -0,0 +1,879 @@
+/* $Id: depth.c,v 1.1 1999/08/19 00:55:41 jtg Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version: 3.1
+ *
+ * Copyright (C) 1999 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.
+ */
+
+
+/*
+ * Depth buffer functions
+ */
+
+
+#ifdef PC_HEADER
+#include "all.h"
+#else
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "context.h"
+#include "enums.h"
+#include "depth.h"
+#include "macros.h"
+#include "types.h"
+#ifdef XFree86Server
+#include "GL/xf86glx.h"
+#endif
+#endif
+
+
+
+/**********************************************************************/
+/***** API Functions *****/
+/**********************************************************************/
+
+
+
+void gl_ClearDepth( GLcontext* ctx, GLclampd depth )
+{
+ ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glClearDepth");
+ ctx->Depth.Clear = (GLfloat) CLAMP( depth, 0.0, 1.0 );
+ if (ctx->Driver.ClearDepth)
+ (*ctx->Driver.ClearDepth)( ctx, ctx->Depth.Clear );
+}
+
+
+
+void gl_DepthFunc( GLcontext* ctx, GLenum func )
+{
+ ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glDepthFunc");
+
+ if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
+ fprintf(stderr, "glDepthFunc %s\n", gl_lookup_enum_by_nr(func));
+
+
+ switch (func) {
+ case GL_NEVER:
+ case GL_LESS: /* (default) pass if incoming z < stored z */
+ case GL_GEQUAL:
+ case GL_LEQUAL:
+ case GL_GREATER:
+ case GL_NOTEQUAL:
+ case GL_EQUAL:
+ case GL_ALWAYS:
+ if (ctx->Depth.Func != func) {
+ ctx->Depth.Func = func;
+ ctx->NewState |= NEW_RASTER_OPS;
+ if (ctx->Driver.DepthFunc) {
+ (*ctx->Driver.DepthFunc)( ctx, func );
+ }
+ }
+ break;
+ default:
+ gl_error( ctx, GL_INVALID_ENUM, "glDepth.Func" );
+ }
+}
+
+
+
+void gl_DepthMask( GLcontext* ctx, GLboolean flag )
+{
+ ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glDepthMask");
+
+ if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
+ fprintf(stderr, "glDepthMask %d\n", flag);
+
+ /*
+ * GL_TRUE indicates depth buffer writing is enabled (default)
+ * GL_FALSE indicates depth buffer writing is disabled
+ */
+ if (ctx->Depth.Mask != flag) {
+ ctx->Depth.Mask = flag;
+ ctx->NewState |= NEW_RASTER_OPS;
+ if (ctx->Driver.DepthMask) {
+ (*ctx->Driver.DepthMask)( ctx, flag );
+ }
+ }
+}
+
+
+
+/**********************************************************************/
+/***** Depth Testing Functions *****/
+/**********************************************************************/
+
+
+/*
+ * Depth test horizontal spans of fragments. These functions are called
+ * via ctx->Driver.depth_test_span only.
+ *
+ * Input: n - number of pixels in the span
+ * x, y - location of leftmost pixel in span in window coords
+ * z - array [n] of integer depth values
+ * In/Out: mask - array [n] of flags (1=draw pixel, 0=don't draw)
+ * Return: number of pixels which passed depth test
+ */
+
+
+/*
+ * glDepthFunc( any ) and glDepthMask( GL_TRUE or GL_FALSE ).
+ */
+GLuint gl_depth_test_span_generic( GLcontext* ctx,
+ GLuint n, GLint x, GLint y,
+ const GLdepth z[],
+ GLubyte mask[] )
+{
+ GLdepth *zptr = Z_ADDRESS( ctx, x, y );
+ GLubyte *m = mask;
+ GLuint i;
+ GLuint passed = 0;
+
+ /* switch cases ordered from most frequent to less frequent */
+ switch (ctx->Depth.Func) {
+ case GL_LESS:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] < *zptr) {
+ /* pass */
+ *zptr = z[i];
+ passed++;
+ }
+ else {
+ /* fail */
+ *m = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] < *zptr) {
+ /* pass */
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_LEQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] <= *zptr) {
+ *zptr = z[i];
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] <= *zptr) {
+ /* pass */
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_GEQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] >= *zptr) {
+ *zptr = z[i];
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] >= *zptr) {
+ /* pass */
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_GREATER:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] > *zptr) {
+ *zptr = z[i];
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] > *zptr) {
+ /* pass */
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_NOTEQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] != *zptr) {
+ *zptr = z[i];
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] != *zptr) {
+ /* pass */
+ passed++;
+ }
+ else {
+ *m = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_EQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] == *zptr) {
+ *zptr = z[i];
+ passed++;
+ }
+ else {
+ *m =0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ if (z[i] == *zptr) {
+ /* pass */
+ passed++;
+ }
+ else {
+ *m =0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_ALWAYS:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0;i<n;i++,zptr++,m++) {
+ if (*m) {
+ *zptr = z[i];
+ passed++;
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer or mask */
+ passed = n;
+ }
+ break;
+ case GL_NEVER:
+ for (i=0;i<n;i++) {
+ mask[i] = 0;
+ }
+ break;
+ default:
+ gl_problem(ctx, "Bad depth func in gl_depth_test_span_generic");
+ } /*switch*/
+
+ return passed;
+}
+
+
+
+/*
+ * glDepthFunc(GL_LESS) and glDepthMask(GL_TRUE).
+ */
+GLuint gl_depth_test_span_less( GLcontext* ctx,
+ GLuint n, GLint x, GLint y, const GLdepth z[],
+ GLubyte mask[] )
+{
+ GLdepth *zptr = Z_ADDRESS( ctx, x, y );
+ GLuint i;
+ GLuint passed = 0;
+
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ if (z[i] < zptr[i]) {
+ /* pass */
+ zptr[i] = z[i];
+ passed++;
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ return passed;
+}
+
+
+/*
+ * glDepthFunc(GL_GREATER) and glDepthMask(GL_TRUE).
+ */
+GLuint gl_depth_test_span_greater( GLcontext* ctx,
+ GLuint n, GLint x, GLint y,
+ const GLdepth z[],
+ GLubyte mask[] )
+{
+ GLdepth *zptr = Z_ADDRESS( ctx, x, y );
+ GLuint i;
+ GLuint passed = 0;
+
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ if (z[i] > zptr[i]) {
+ /* pass */
+ zptr[i] = z[i];
+ passed++;
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ return passed;
+}
+
+
+
+/*
+ * Depth test an array of randomly positioned fragments.
+ */
+
+
+#define ZADDR_SETUP GLdepth *depthbuffer = ctx->Buffer->Depth; \
+ GLint width = ctx->Buffer->Width;
+
+#define ZADDR( X, Y ) (depthbuffer + (Y) * width + (X) )
+
+
+
+/*
+ * glDepthFunc( any ) and glDepthMask( GL_TRUE or GL_FALSE ).
+ */
+void gl_depth_test_pixels_generic( GLcontext* ctx,
+ GLuint n, const GLint x[], const GLint y[],
+ const GLdepth z[], GLubyte mask[] )
+{
+ register GLdepth *zptr;
+ register GLuint i;
+
+ /* switch cases ordered from most frequent to less frequent */
+ switch (ctx->Depth.Func) {
+ case GL_LESS:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] < *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] < *zptr) {
+ /* pass */
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_LEQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] <= *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] <= *zptr) {
+ /* pass */
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_GEQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] >= *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] >= *zptr) {
+ /* pass */
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_GREATER:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] > *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] > *zptr) {
+ /* pass */
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_NOTEQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] != *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] != *zptr) {
+ /* pass */
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_EQUAL:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] == *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] == *zptr) {
+ /* pass */
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+ }
+ break;
+ case GL_ALWAYS:
+ if (ctx->Depth.Mask) {
+ /* Update Z buffer */
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ *zptr = z[i];
+ }
+ }
+ }
+ else {
+ /* Don't update Z buffer or mask */
+ }
+ break;
+ case GL_NEVER:
+ /* depth test never passes */
+ for (i=0;i<n;i++) {
+ mask[i] = 0;
+ }
+ break;
+ default:
+ gl_problem(ctx, "Bad depth func in gl_depth_test_pixels_generic");
+ } /*switch*/
+}
+
+
+
+/*
+ * glDepthFunc( GL_LESS ) and glDepthMask( GL_TRUE ).
+ */
+void gl_depth_test_pixels_less( GLcontext* ctx,
+ GLuint n, const GLint x[], const GLint y[],
+ const GLdepth z[], GLubyte mask[] )
+{
+ GLdepth *zptr;
+ GLuint i;
+
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] < *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+}
+
+
+/*
+ * glDepthFunc( GL_GREATER ) and glDepthMask( GL_TRUE ).
+ */
+void gl_depth_test_pixels_greater( GLcontext* ctx,
+ GLuint n, const GLint x[], const GLint y[],
+ const GLdepth z[], GLubyte mask[] )
+{
+ GLdepth *zptr;
+ GLuint i;
+
+ for (i=0; i<n; i++) {
+ if (mask[i]) {
+ zptr = Z_ADDRESS(ctx,x[i],y[i]);
+ if (z[i] > *zptr) {
+ /* pass */
+ *zptr = z[i];
+ }
+ else {
+ /* fail */
+ mask[i] = 0;
+ }
+ }
+ }
+}
+
+
+
+
+/**********************************************************************/
+/***** Read Depth Buffer *****/
+/**********************************************************************/
+
+
+/*
+ * Return a span of depth values from the depth buffer as floats in [0,1].
+ * This function is only called through Driver.read_depth_span_float()
+ * Input: n - how many pixels
+ * x,y - location of first pixel
+ * Output: depth - the array of depth values
+ */
+void gl_read_depth_span_float( GLcontext* ctx,
+ GLuint n, GLint x, GLint y, GLfloat depth[] )
+{
+ GLdepth *zptr;
+ GLfloat scale;
+ GLuint i;
+
+ scale = 1.0F / DEPTH_SCALE;
+
+ if (ctx->Buffer->Depth) {
+ zptr = Z_ADDRESS( ctx, x, y );
+ for (i=0;i<n;i++) {
+ depth[i] = (GLfloat) zptr[i] * scale;
+ }
+ }
+ else {
+ for (i=0;i<n;i++) {
+ depth[i] = 0.0F;
+ }
+ }
+}
+
+
+/*
+ * Return a span of depth values from the depth buffer as integers in
+ * [0,MAX_DEPTH].
+ * This function is only called through Driver.read_depth_span_int()
+ * Input: n - how many pixels
+ * x,y - location of first pixel
+ * Output: depth - the array of depth values
+ */
+void gl_read_depth_span_int( GLcontext* ctx,
+ GLuint n, GLint x, GLint y, GLdepth depth[] )
+{
+ if (ctx->Buffer->Depth) {
+ GLdepth *zptr = Z_ADDRESS( ctx, x, y );
+ MEMCPY( depth, zptr, n * sizeof(GLdepth) );
+ }
+ else {
+ GLuint i;
+ for (i=0;i<n;i++) {
+ depth[i] = 0;
+ }
+ }
+}
+
+
+
+/**********************************************************************/
+/***** Allocate and Clear Depth Buffer *****/
+/**********************************************************************/
+
+
+
+/*
+ * Allocate a new depth buffer. If there's already a depth buffer allocated
+ * it will be free()'d. The new depth buffer will be uniniitalized.
+ * This function is only called through Driver.alloc_depth_buffer.
+ */
+void gl_alloc_depth_buffer( GLcontext* ctx )
+{
+ /* deallocate current depth buffer if present */
+ if (ctx->Buffer->Depth) {
+ free(ctx->Buffer->Depth);
+ ctx->Buffer->Depth = NULL;
+ }
+
+ /* allocate new depth buffer, but don't initialize it */
+ ctx->Buffer->Depth = (GLdepth *) malloc( ctx->Buffer->Width
+ * ctx->Buffer->Height
+ * sizeof(GLdepth) );
+ if (!ctx->Buffer->Depth) {
+ /* out of memory */
+ ctx->Depth.Test = GL_FALSE;
+ gl_error( ctx, GL_OUT_OF_MEMORY, "Couldn't allocate depth buffer" );
+ }
+}
+
+
+
+
+/*
+ * Clear the depth buffer. If the depth buffer doesn't exist yet we'll
+ * allocate it now.
+ * This function is only called through Driver.clear_depth_buffer.
+ */
+void gl_clear_depth_buffer( GLcontext* ctx )
+{
+ GLdepth clear_value = (GLdepth) (ctx->Depth.Clear * DEPTH_SCALE);
+
+ if (ctx->Visual->DepthBits==0 || !ctx->Buffer->Depth || !ctx->Depth.Mask) {
+ /* no depth buffer, or writing to it is disabled */
+ return;
+ }
+
+ /* The loops in this function have been written so the IRIX 5.3
+ * C compiler can unroll them. Hopefully other compilers can too!
+ */
+
+ if (ctx->Scissor.Enabled) {
+ /* only clear scissor region */
+ GLint y;
+ for (y=ctx->Buffer->Ymin; y<=ctx->Buffer->Ymax; y++) {
+ GLdepth *d = Z_ADDRESS( ctx, ctx->Buffer->Xmin, y );
+ GLint n = ctx->Buffer->Xmax - ctx->Buffer->Xmin + 1;
+ do {
+ *d++ = clear_value;
+ n--;
+ } while (n);
+ }
+ }
+ else {
+ /* clear whole buffer */
+ if (sizeof(GLdepth)==2 && (clear_value&0xff)==(clear_value>>8)) {
+ /* lower and upper bytes of clear_value are same, use MEMSET */
+ MEMSET( ctx->Buffer->Depth, clear_value&0xff,
+ 2*ctx->Buffer->Width*ctx->Buffer->Height);
+ }
+ else {
+ GLdepth *d = ctx->Buffer->Depth;
+ GLint n = ctx->Buffer->Width * ctx->Buffer->Height;
+ while (n>=16) {
+ d[0] = clear_value; d[1] = clear_value;
+ d[2] = clear_value; d[3] = clear_value;
+ d[4] = clear_value; d[5] = clear_value;
+ d[6] = clear_value; d[7] = clear_value;
+ d[8] = clear_value; d[9] = clear_value;
+ d[10] = clear_value; d[11] = clear_value;
+ d[12] = clear_value; d[13] = clear_value;
+ d[14] = clear_value; d[15] = clear_value;
+ d += 16;
+ n -= 16;
+ }
+ while (n>0) {
+ *d++ = clear_value;
+ n--;
+ }
+ }
+ }
+}
+
+
+