VGA: Breakup biosfn_scroll.

Rename biosfn_scroll to vgafb_scroll.
Break function up into per-mode scroll function.
Pass row/col params in a 'struct cursorpos'.
Encode direction as sign in nblines.
Move parameter checking to callers.
Add enhancement to 'attr' for using mode specific default attribute.
Also, make get_cursor_pos local to vga.c.

3 files changed, 217 insertions, 165 deletions

diff --git a/vgasrc/vga.c b/vgasrc/vga.c
index 06b3993d..180fc991 100644
--- a/vgasrc/vga.c
+++ b/vgasrc/vga.c
@@ -30,7 +30,7 @@
 
 #define SET_VGA(var, val) SET_FARVAR(get_global_seg(), (var), (val))
 
-inline void
+static inline void
 call16_vgaint(u32 eax, u32 ebx)
 {
     asm volatile(
@@ -117,7 +117,7 @@ set_cursor_pos(struct cursorpos cp)
     vgahw_set_cursor_pos(address);
 }
 
-struct cursorpos
+static struct cursorpos
 get_cursor_pos(u8 page)
 {
     if (page == 0xff)
@@ -189,17 +189,9 @@ check_scroll(struct cursorpos cp)
     }
     // Do we need to scroll ?
     if (cp.y == nbrows) {
-        // Get the mode
-        struct vgamode_s *vmode_g = find_vga_entry(GET_BDA(video_mode));
-        if (!vmode_g)
-            return cp;
-
-        if (GET_GLOBAL(vmode_g->memmodel) & TEXT)
-            biosfn_scroll(0x01, 0x07, 0, 0, nbrows - 1, nbcols - 1, cp.page,
-                          SCROLL_UP);
-        else
-            biosfn_scroll(0x01, 0x00, 0, 0, nbrows - 1, nbcols - 1, cp.page,
-                          SCROLL_UP);
+        struct cursorpos ul = {0, 0, cp.page};
+        struct cursorpos lr = {nbcols-1, nbrows-1, cp.page};
+        vgafb_scroll(1, -1, ul, lr);
         cp.y--;
     }
 
@@ -494,17 +486,36 @@ handle_1005(struct bregs *regs)
 }
 
 static void
+verify_scroll(struct bregs *regs, int dir)
+{
+    u8 page = GET_BDA(video_page);
+    struct cursorpos ul = {regs->cl, regs->ch, page};
+    struct cursorpos lr = {regs->dl, regs->dh, page};
+
+    if (ul.x > lr.x || ul.y > lr.y)
+        return;
+
+    u16 nbrows = GET_BDA(video_rows) + 1;
+    u16 nbcols = GET_BDA(video_cols);
+
+    if (lr.y >= nbrows)
+        lr.y = nbrows - 1;
+    if (lr.x >= nbcols)
+        lr.x = nbcols - 1;
+
+    vgafb_scroll(dir * regs->al, regs->bh, ul, lr);
+}
+
+static void
 handle_1006(struct bregs *regs)
 {
-    biosfn_scroll(regs->al, regs->bh, regs->ch, regs->cl, regs->dh, regs->dl
-                  , 0xFF, SCROLL_UP);
+    verify_scroll(regs, 1);
 }
 
 static void
 handle_1007(struct bregs *regs)
 {
-    biosfn_scroll(regs->al, regs->bh, regs->ch, regs->cl, regs->dh, regs->dl
-                  , 0xFF, SCROLL_DOWN);
+    verify_scroll(regs, -1);
 }
 
 static void
diff --git a/vgasrc/vgafb.c b/vgasrc/vgafb.c
index f1b46d49..6790570d 100644
--- a/vgasrc/vgafb.c
+++ b/vgasrc/vgafb.c
@@ -53,6 +53,58 @@ vgamem_fill_pl4(u8 xstart, u8 ystart, u8 cols, u8 nbcols, u8 cheight,
 }
 
 static void
+scroll_pl4(struct vgamode_s *vmode_g, int nblines, int attr
+           , struct cursorpos ul, struct cursorpos lr)
+{
+    if (attr < 0)
+        attr = 0;
+    u8 dir = SCROLL_UP;
+    if (nblines < 0) {
+        nblines = -nblines;
+        dir = SCROLL_DOWN;
+    }
+    // Get the dimensions
+    u16 nbrows = GET_BDA(video_rows) + 1;
+    u16 nbcols = GET_BDA(video_cols);
+    if (nblines > nbrows)
+        nblines = 0;
+    u8 cols = lr.x - ul.x + 1;
+
+    struct VideoParam_s *vparam_g = GET_GLOBAL(vmode_g->vparam);
+    u8 cheight = GET_GLOBAL(vparam_g->cheight);
+    if (nblines == 0 && ul.y == 0 && ul.x == 0 && lr.y == nbrows - 1
+        && lr.x == nbcols - 1) {
+        outw(0x0205, VGAREG_GRDC_ADDRESS);
+        memset_far(GET_GLOBAL(vmode_g->sstart), 0, attr,
+                   nbrows * nbcols * cheight);
+        outw(0x0005, VGAREG_GRDC_ADDRESS);
+        return;
+    }
+    if (dir == SCROLL_UP) {
+        u16 i;
+        for (i = ul.y; i <= lr.y; i++)
+            if ((i + nblines > lr.y) || (nblines == 0))
+                vgamem_fill_pl4(ul.x, i, cols, nbcols, cheight,
+                                attr);
+            else
+                vgamem_copy_pl4(ul.x, i + nblines, i, cols,
+                                nbcols, cheight);
+        return;
+    }
+    u16 i;
+    for (i = lr.y; i >= ul.y; i--) {
+        if ((i < ul.y + nblines) || (nblines == 0))
+            vgamem_fill_pl4(ul.x, i, cols, nbcols, cheight,
+                            attr);
+        else
+            vgamem_copy_pl4(ul.x, i, i - nblines, cols,
+                            nbcols, cheight);
+        if (i > lr.y)
+            break;
+    }
+}
+
+static void
 vgamem_copy_cga(u8 xstart, u8 ysrc, u8 ydest, u8 cols, u8 nbcols,
                 u8 cheight)
 {
@@ -83,180 +135,170 @@ vgamem_fill_cga(u8 xstart, u8 ystart, u8 cols, u8 nbcols, u8 cheight,
             memset_far(SEG_CTEXT, (void*)(dest + (i >> 1) * nbcols), attr, cols);
 }
 
-void
-clear_screen(struct vgamode_s *vmode_g)
+static void
+scroll_cga(struct vgamode_s *vmode_g, int nblines, int attr
+            , struct cursorpos ul, struct cursorpos lr)
 {
-    if (GET_GLOBAL(vmode_g->memmodel) & TEXT) {
-        memset16_far(GET_GLOBAL(vmode_g->sstart), 0, 0x0720, 32*1024);
+    if (attr < 0)
+        attr = 0;
+    u8 dir = SCROLL_UP;
+    if (nblines < 0) {
+        nblines = -nblines;
+        dir = SCROLL_DOWN;
+    }
+    // Get the dimensions
+    u16 nbrows = GET_BDA(video_rows) + 1;
+    u16 nbcols = GET_BDA(video_cols);
+    if (nblines > nbrows)
+        nblines = 0;
+    u8 cols = lr.x - ul.x + 1;
+
+    struct VideoParam_s *vparam_g = GET_GLOBAL(vmode_g->vparam);
+    u8 cheight = GET_GLOBAL(vparam_g->cheight);
+    u8 bpp = GET_GLOBAL(vmode_g->pixbits);
+    if (nblines == 0 && ul.y == 0 && ul.x == 0 && lr.y == nbrows - 1
+        && lr.x == nbcols - 1) {
+        memset_far(GET_GLOBAL(vmode_g->sstart), 0, attr,
+                   nbrows * nbcols * cheight * bpp);
         return;
     }
-    if (GET_GLOBAL(vmode_g->svgamode) < 0x0d) {
-        memset16_far(GET_GLOBAL(vmode_g->sstart), 0, 0x0000, 32*1024);
+    if (bpp == 2) {
+        ul.x <<= 1;
+        cols <<= 1;
+        nbcols <<= 1;
+    }
+    // if Scroll up
+    if (dir == SCROLL_UP) {
+        u16 i;
+        for (i = ul.y; i <= lr.y; i++)
+            if ((i + nblines > lr.y) || (nblines == 0))
+                vgamem_fill_cga(ul.x, i, cols, nbcols, cheight,
+                                attr);
+            else
+                vgamem_copy_cga(ul.x, i + nblines, i, cols,
+                                nbcols, cheight);
         return;
     }
-    outb(0x02, VGAREG_SEQU_ADDRESS);
-    u8 mmask = inb(VGAREG_SEQU_DATA);
-    outb(0x0f, VGAREG_SEQU_DATA);   // all planes
-    memset16_far(GET_GLOBAL(vmode_g->sstart), 0, 0x0000, 64*1024);
-    outb(mmask, VGAREG_SEQU_DATA);
+    u16 i;
+    for (i = lr.y; i >= ul.y; i--) {
+        if ((i < ul.y + nblines) || (nblines == 0))
+            vgamem_fill_cga(ul.x, i, cols, nbcols, cheight,
+                            attr);
+        else
+            vgamem_copy_cga(ul.x, i, i - nblines, cols,
+                            nbcols, cheight);
+        if (i > lr.y)
+            break;
+    }
 }
 
-void
-biosfn_scroll(u8 nblines, u8 attr, u8 rul, u8 cul, u8 rlr, u8 clr, u8 page,
-              u8 dir)
+static void
+scroll_text(struct vgamode_s *vmode_g, int nblines, int attr
+            , struct cursorpos ul, struct cursorpos lr)
 {
-    // page == 0xFF if current
-    if (rul > rlr)
-        return;
-    if (cul > clr)
-        return;
-
-    // Get the mode
-    struct vgamode_s *vmode_g = find_vga_entry(GET_BDA(video_mode));
-    if (!vmode_g)
-        return;
-
+    if (attr < 0)
+        attr = 0x07;
+    u8 dir = SCROLL_UP;
+    if (nblines < 0) {
+        nblines = -nblines;
+        dir = SCROLL_DOWN;
+    }
     // Get the dimensions
     u16 nbrows = GET_BDA(video_rows) + 1;
     u16 nbcols = GET_BDA(video_cols);
 
-    // Get the current page
-    if (page == 0xFF)
-        page = GET_BDA(video_page);
-
-    if (rlr >= nbrows)
-        rlr = nbrows - 1;
-    if (clr >= nbcols)
-        clr = nbcols - 1;
     if (nblines > nbrows)
         nblines = 0;
-    u8 cols = clr - cul + 1;
+    u8 cols = lr.x - ul.x + 1;
 
-    if (GET_GLOBAL(vmode_g->memmodel) & TEXT) {
-        // Compute the address
-        void *address_far = (void*)(SCREEN_MEM_START(nbcols, nbrows, page));
-        dprintf(3, "Scroll, address %p (%d %d %02x)\n"
-                , address_far, nbrows, nbcols, page);
-
-        if (nblines == 0 && rul == 0 && cul == 0 && rlr == nbrows - 1
-            && clr == nbcols - 1) {
-            memset16_far(GET_GLOBAL(vmode_g->sstart), address_far
-                         , (u16)attr * 0x100 + ' ', nbrows * nbcols * 2);
-        } else {                // if Scroll up
-            if (dir == SCROLL_UP) {
-                u16 i;
-                for (i = rul; i <= rlr; i++)
-                    if ((i + nblines > rlr) || (nblines == 0))
-                        memset16_far(GET_GLOBAL(vmode_g->sstart)
-                                     , address_far + (i * nbcols + cul) * 2
-                                     , (u16)attr * 0x100 + ' ', cols * 2);
-                    else
-                        memcpy16_far(GET_GLOBAL(vmode_g->sstart)
-                                     , address_far + (i * nbcols + cul) * 2
-                                     , GET_GLOBAL(vmode_g->sstart)
-                                     , (void*)(((i + nblines) * nbcols + cul) * 2)
-                                     , cols * 2);
-            } else {
-                u16 i;
-                for (i = rlr; i >= rul; i--) {
-                    if ((i < rul + nblines) || (nblines == 0))
-                        memset16_far(GET_GLOBAL(vmode_g->sstart)
-                                     , address_far + (i * nbcols + cul) * 2
-                                     , (u16)attr * 0x100 + ' ', cols * 2);
-                    else
-                        memcpy16_far(GET_GLOBAL(vmode_g->sstart)
-                                     , address_far + (i * nbcols + cul) * 2
-                                     , GET_GLOBAL(vmode_g->sstart)
-                                     , (void*)(((i - nblines) * nbcols + cul) * 2)
-                                     , cols * 2);
-                    if (i > rlr)
-                        break;
-                }
-            }
-        }
+    // Compute the address
+    void *address_far = (void*)(SCREEN_MEM_START(nbcols, nbrows, ul.page));
+    dprintf(3, "Scroll, address %p (%d %d %02x)\n"
+            , address_far, nbrows, nbcols, ul.page);
+
+    if (nblines == 0 && ul.y == 0 && ul.x == 0 && lr.y == nbrows - 1
+        && lr.x == nbcols - 1) {
+        memset16_far(GET_GLOBAL(vmode_g->sstart), address_far
+                     , (u16)attr * 0x100 + ' ', nbrows * nbcols * 2);
         return;
     }
+    if (dir == SCROLL_UP) {
+        u16 i;
+        for (i = ul.y; i <= lr.y; i++)
+            if ((i + nblines > lr.y) || (nblines == 0))
+                memset16_far(GET_GLOBAL(vmode_g->sstart)
+                             , address_far + (i * nbcols + ul.x) * 2
+                             , (u16)attr * 0x100 + ' ', cols * 2);
+            else
+                memcpy16_far(GET_GLOBAL(vmode_g->sstart)
+                             , address_far + (i * nbcols + ul.x) * 2
+                             , GET_GLOBAL(vmode_g->sstart)
+                             , (void*)(((i + nblines) * nbcols + ul.x) * 2)
+                             , cols * 2);
+        return;
+    }
+
+    u16 i;
+    for (i = lr.y; i >= ul.y; i--) {
+        if ((i < ul.y + nblines) || (nblines == 0))
+            memset16_far(GET_GLOBAL(vmode_g->sstart)
+                         , address_far + (i * nbcols + ul.x) * 2
+                         , (u16)attr * 0x100 + ' ', cols * 2);
+        else
+            memcpy16_far(GET_GLOBAL(vmode_g->sstart)
+                         , address_far + (i * nbcols + ul.x) * 2
+                         , GET_GLOBAL(vmode_g->sstart)
+                         , (void*)(((i - nblines) * nbcols + ul.x) * 2)
+                         , cols * 2);
+        if (i > lr.y)
+            break;
+    }
+}
+
+void
+vgafb_scroll(int nblines, int attr, struct cursorpos ul, struct cursorpos lr)
+{
+    // Get the mode
+    struct vgamode_s *vmode_g = find_vga_entry(GET_BDA(video_mode));
+    if (!vmode_g)
+        return;
 
     // FIXME gfx mode not complete
-    struct VideoParam_s *vparam_g = GET_GLOBAL(vmode_g->vparam);
-    u8 cheight = GET_GLOBAL(vparam_g->cheight);
     switch (GET_GLOBAL(vmode_g->memmodel)) {
+    case CTEXT:
+    case MTEXT:
+        scroll_text(vmode_g, nblines, attr, ul, lr);
+        break;
     case PLANAR4:
     case PLANAR1:
-        if (nblines == 0 && rul == 0 && cul == 0 && rlr == nbrows - 1
-            && clr == nbcols - 1) {
-            outw(0x0205, VGAREG_GRDC_ADDRESS);
-            memset_far(GET_GLOBAL(vmode_g->sstart), 0, attr,
-                       nbrows * nbcols * cheight);
-            outw(0x0005, VGAREG_GRDC_ADDRESS);
-        } else {            // if Scroll up
-            if (dir == SCROLL_UP) {
-                u16 i;
-                for (i = rul; i <= rlr; i++)
-                    if ((i + nblines > rlr) || (nblines == 0))
-                        vgamem_fill_pl4(cul, i, cols, nbcols, cheight,
-                                        attr);
-                    else
-                        vgamem_copy_pl4(cul, i + nblines, i, cols,
-                                        nbcols, cheight);
-            } else {
-                u16 i;
-                for (i = rlr; i >= rul; i--) {
-                    if ((i < rul + nblines) || (nblines == 0))
-                        vgamem_fill_pl4(cul, i, cols, nbcols, cheight,
-                                        attr);
-                    else
-                        vgamem_copy_pl4(cul, i, i - nblines, cols,
-                                        nbcols, cheight);
-                    if (i > rlr)
-                        break;
-                }
-            }
-        }
+        scroll_pl4(vmode_g, nblines, attr, ul, lr);
         break;
-    case CGA: {
-        u8 bpp = GET_GLOBAL(vmode_g->pixbits);
-        if (nblines == 0 && rul == 0 && cul == 0 && rlr == nbrows - 1
-            && clr == nbcols - 1) {
-            memset_far(GET_GLOBAL(vmode_g->sstart), 0, attr,
-                       nbrows * nbcols * cheight * bpp);
-        } else {
-            if (bpp == 2) {
-                cul <<= 1;
-                cols <<= 1;
-                nbcols <<= 1;
-            }
-            // if Scroll up
-            if (dir == SCROLL_UP) {
-                u16 i;
-                for (i = rul; i <= rlr; i++)
-                    if ((i + nblines > rlr) || (nblines == 0))
-                        vgamem_fill_cga(cul, i, cols, nbcols, cheight,
-                                        attr);
-                    else
-                        vgamem_copy_cga(cul, i + nblines, i, cols,
-                                        nbcols, cheight);
-            } else {
-                u16 i;
-                for (i = rlr; i >= rul; i--) {
-                    if ((i < rul + nblines) || (nblines == 0))
-                        vgamem_fill_cga(cul, i, cols, nbcols, cheight,
-                                        attr);
-                    else
-                        vgamem_copy_cga(cul, i, i - nblines, cols,
-                                        nbcols, cheight);
-                    if (i > rlr)
-                        break;
-                }
-            }
-        }
+    case CGA:
+        scroll_cga(vmode_g, nblines, attr, ul, lr);
         break;
-    }
     default:
         dprintf(1, "Scroll in graphics mode\n");
     }
 }
 
+void
+clear_screen(struct vgamode_s *vmode_g)
+{
+    if (GET_GLOBAL(vmode_g->memmodel) & TEXT) {
+        memset16_far(GET_GLOBAL(vmode_g->sstart), 0, 0x0720, 32*1024);
+        return;
+    }
+    if (GET_GLOBAL(vmode_g->svgamode) < 0x0d) {
+        memset16_far(GET_GLOBAL(vmode_g->sstart), 0, 0x0000, 32*1024);
+        return;
+    }
+    outb(0x02, VGAREG_SEQU_ADDRESS);
+    u8 mmask = inb(VGAREG_SEQU_DATA);
+    outb(0x0f, VGAREG_SEQU_DATA);   // all planes
+    memset16_far(GET_GLOBAL(vmode_g->sstart), 0, 0x0000, 64*1024);
+    outb(mmask, VGAREG_SEQU_DATA);
+}
+
 
 /****************************************************************
  * Read/write characters to screen
diff --git a/vgasrc/vgatables.h b/vgasrc/vgatables.h
index 60794350..aa21108e 100644
--- a/vgasrc/vgatables.h
+++ b/vgasrc/vgatables.h
@@ -162,12 +162,11 @@ struct carattr {
 struct cursorpos {
     u8 x, y, page;
 };
-struct cursorpos get_cursor_pos(u8 page);
 
 // vgafb.c
 void clear_screen(struct vgamode_s *vmode_g);
-void biosfn_scroll(u8 nblines, u8 attr, u8 rul, u8 cul, u8 rlr, u8 clr
-                   , u8 page, u8 dir);
+void vgafb_scroll(int nblines, int attr
+                  , struct cursorpos ul, struct cursorpos lr);
 void vgafb_write_char(struct cursorpos cp, struct carattr ca);
 struct carattr vgafb_read_char(struct cursorpos cp);
 void biosfn_write_pixel(u8 BH, u8 AL, u16 CX, u16 DX);