Add code for manipulating "direct" style linear RGB framebuffers that
may be in high memory.
Signed-off-by: Kevin O'Connor <ke...@koconnor.net>
---
vgasrc/vgabios.h | 1 +
vgasrc/vgafb.c | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 112 insertions(+)
diff --git a/vgasrc/vgabios.h b/vgasrc/vgabios.h
index 73c0697..8fe65d4 100644
--- a/vgasrc/vgabios.h
+++ b/vgasrc/vgabios.h
@@ -60,6 +60,7 @@ struct vgamode_s {
struct gfx_op {
struct vgamode_s *vmode_g;
u32 linelength;
+ u32 displaystart;
u8 op;
u16 x, y;
diff --git a/vgasrc/vgafb.c b/vgasrc/vgafb.c
index 31bf5de..b90a956 100644
--- a/vgasrc/vgafb.c
+++ b/vgasrc/vgafb.c
@@ -181,6 +181,113 @@ gfx_packed(struct gfx_op *op)
/****************************************************************
+ * Direct framebuffers in high mem
+ ****************************************************************/
+
+// Use int 1587 call to copy memory to/from the framebuffer.
+static void
+memcpy_high(void *dest, void *src, u32 len)
+{
+ u64 gdt[6];
+ gdt[2] = GDT_DATA | GDT_LIMIT(0xfffff) | GDT_BASE((u32)src);
+ gdt[3] = GDT_DATA | GDT_LIMIT(0xfffff) | GDT_BASE((u32)dest);
+
+ // Call int 1587 to copy data.
+ len/=2;
+ u32 flags;
+ u32 eax = 0x8700;
+ u32 si = (u32)&gdt;
+ SET_SEG(ES, GET_SEG(SS));
+ asm volatile(
+ "stc\n"
+ "int $0x15\n"
+ "cli\n"
+ "cld\n"
+ "pushfl\n"
+ "popl %0\n"
+ : "=r" (flags), "+a" (eax), "+S" (si), "+c" (len)
+ : : "cc", "memory");
+}
+
+static void
+memmove_stride_high(void *dst, void *src, int copylen, int stride, int lines)
+{
+ if (src < dst) {
+ dst += stride * (lines - 1);
+ src += stride * (lines - 1);
+ stride = -stride;
+ }
+ for (; lines; lines--, dst+=stride, src+=stride)
+ memcpy_high(dst, src, copylen);
+}
+
+// Map a CGA color to a "direct" mode rgb value.
+static u32
+get_color(int depth, u8 attr)
+{
+ int rbits, gbits, bbits;
+ switch (depth) {
+ case 15: rbits=5; gbits=5; bbits=5; break;
+ case 16: rbits=5; gbits=6; bbits=5; break;
+ default:
+ case 24: rbits=8; gbits=8; bbits=8; break;
+ }
+ int h = (attr&8) ? 1 : 0;
+ int r = (attr&4) ? 2 : 0, g = (attr&2) ? 2 : 0, b = (attr&1) ? 2 : 0;
+ if ((attr & 0xf) == 6)
+ g = 1;
+ return ((((((1<<rbits) - 1) * (r + h) + 1) / 3) << (gbits+bbits))
+ + (((((1<<gbits) - 1) * (g + h) + 1) / 3) << bbits)
+ + ((((1<<bbits) - 1) * (b + h) + 1) / 3));
+}
+
+static void
+gfx_direct(struct gfx_op *op)
+{
+ void *fb = (void*)GET_GLOBAL(VBE_framebuffer);
+ if (!fb)
+ return;
+ int depth = GET_GLOBAL(op->vmode_g->depth);
+ int bypp = DIV_ROUND_UP(depth, 8);
+ void *dest_far = (fb + op->displaystart + op->y * op->linelength
+ + op->x * bypp);
+ switch (op->op) {
+ default:
+ case GO_READ8:
+ // XXX - not implemented.
+ break;
+ case GO_WRITE8: {
+ u8 data[64];
+ int i;
+ for (i=0; i<8; i++)
+ *(u32*)&data[i*bypp] = get_color(depth, op->pixels[i]);
+ memcpy_high(dest_far, MAKE_FLATPTR(GET_SEG(SS), data), bypp * 8);
+ break;
+ }
+ case GO_MEMSET: {
+ u32 color = get_color(depth, op->pixels[0]);
+ u8 data[64];
+ int i;
+ for (i=0; i<8; i++)
+ *(u32*)&data[i*bypp] = color;
+ memcpy_high(dest_far, MAKE_FLATPTR(GET_SEG(SS), data), bypp * 8);
+ memcpy_high(dest_far + bypp * 8, dest_far, op->xlen * bypp - bypp * 8);
+ for (i=1; i < op->ylen; i++)
+ memcpy_high(dest_far + op->linelength * i
+ , dest_far, op->xlen * bypp);
+ break;
+ }
+ case GO_MEMMOVE: ;
+ void *src_far = (fb + op->displaystart + op->srcy * op->linelength
+ + op->x * bypp);
+ memmove_stride_high(dest_far, src_far
+ , op->xlen * bypp, op->linelength, op->ylen);
+ break;
+ }
+}
+
+
+/****************************************************************
* Gfx interface
****************************************************************/
@@ -191,6 +298,7 @@ init_gfx_op(struct gfx_op *op, struct vgamode_s *vmode_g)
memset(op, 0, sizeof(*op));
op->vmode_g = vmode_g;
op->linelength = vgahw_get_linelength(vmode_g);
+ op->displaystart = vgahw_get_displaystart(vmode_g);
}
// Issue a graphics operation.
@@ -207,6 +315,9 @@ handle_gfx_op(struct gfx_op *op)
case MM_PACKED:
gfx_packed(op);
break;
+ case MM_DIRECT:
+ gfx_direct(op);
+ break;
default:
break;
}
--
1.9.0
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