Correct VGA text functionality without passthrough

Corrected operation of odd/even chaining and chain4 chaining and other cleanup

diff --git a/palacios/src/devices/vga.c b/palacios/src/devices/vga.c
index a99faae..a507f48 100644 (file)
--- a/palacios/src/devices/vga.c
+++ b/palacios/src/devices/vga.c
@@ -831,7 +831,7 @@ static void render_text(struct vga_internal *vga, void *fb)
     rtw = tw < fw/cw ? tw : fw/cw;
     rth = th < fh/ch ? th : fh/ch;
 
-    
+    PrintDebug("\n");
 
     // Now let's scan by char across the whole thing
     for (y=0;y<th;y++) { 
@@ -842,6 +842,8 @@ static void render_text(struct vga_internal *vga, void *fb)
                ca = *attr;  
                a.val = ca;
 
+               PrintDebug("%c",ct);
+
                // find the character's font bitmap (one byte per row)
                find_text_font_start(vga,(void**)&font,
                                     extended_fontset(vga) ? a.foreground_intensity_or_font_select : 0 ); 
@@ -1134,10 +1136,11 @@ static uint64_t find_offset_write(struct vga_internal *vga, addr_t guest_addr)
     size=(mem_end-mem_start > 65536 ? 65536 : (mem_end-mem_start)); 
 
     if (vga->vga_sequencer.vga_mem_mode.odd_even) { 
-       return (guest_addr-mem_start) % size;
+      // NOT odd/even mode
+      return (guest_addr-mem_start) % size;
     } else {
        // odd/even mode
-       return ((guest_addr-mem_start) >> 1 ) % size;
+      return ((guest_addr-mem_start) >> 1 ) % size;
     }
 }
 
@@ -1154,23 +1157,26 @@ static uint8_t find_map_write(struct vga_internal *vga, addr_t guest_addr)
     uint8_t mm = vga->vga_sequencer.vga_map_mask.val;
 
     if (vga->vga_sequencer.vga_mem_mode.odd_even) { 
-       return mm;
+      // NOT odd/even mode
+      return mm;
     } else {
-       if (guest_addr & 0x1) { 
-           return mm & 0xa;  // 0x1010
-       } else {
-           return mm & 0x5;  // 0x0101
-       }
+      // odd/even mode
+      if (guest_addr & 0x1) { 
+       return mm & 0xa;  // 0x1010
+      } else {
+       return mm & 0x5;  // 0x0101
+      }
     }
 }
 
 static uint8_t find_increment_write(struct vga_internal *vga, addr_t new_guest_addr)
 {
-    if (vga->vga_sequencer.vga_mem_mode.odd_even) { 
-       return 1;
-    } else {
-       return !(new_guest_addr & 0x1);
-    }
+  if (vga->vga_sequencer.vga_mem_mode.odd_even) { 
+    // NOT odd/even mode
+    return 1;
+  } else {
+    return !(new_guest_addr & 0x1);
+  }
 }
 
 
@@ -1184,7 +1190,8 @@ static int vga_write(struct guest_info * core,
     struct vm_device *dev = (struct vm_device *)priv_data;
     struct vga_internal *vga = (struct vga_internal *) dev->private_data;
 
-    PrintDebug("vga: memory write: guest_addr=0x%p len=%u\n",(void*)guest_addr, length);
+    PrintDebug("vga: memory write: guest_addr=0x%p len=%u write_mode=%d\n",(void*)guest_addr, length,
+              vga->vga_graphics_controller.vga_graphics_mode.write_mode);
 
     if (vga->passthrough) { 
        PrintDebug("vga: passthrough write to 0x%p\n", V3_VAddr((void*)guest_addr));
@@ -1499,22 +1506,61 @@ static uint64_t find_offset_read(struct vga_internal *vga, addr_t guest_addr)
     
     size=(mem_end-mem_start > 65536 ? 65536 : (mem_end-mem_start)); 
 
-    if (!vga->vga_sequencer.vga_mem_mode.chain4) { 
-       return (guest_addr-mem_start) % size;
-    } else {
-       // chain4 mode
-       return ((guest_addr - mem_start) >> 2) % size;
+    if (!vga->vga_sequencer.vga_mem_mode.odd_even) { 
+      // odd/even mode takes priority
+      return ((guest_addr-mem_start) >> 1 ) % size;
+    } 
+
+    if (vga->vga_sequencer.vga_mem_mode.chain4) {
+      // otherwise chain4 if it's on
+      return ((guest_addr - mem_start) >> 2) % size;
     }
+
+    // and what you would expect if neither are on
+    return (guest_addr-mem_start) % size;
 }
 
-static uint8_t find_increment_read(struct vga_internal *vga, addr_t new_guest_addr)
+// Given this address
+// which specific map should we write into?
+// Note that unlike with find_map_write, here we are looking
+// for a single map number, not a bit vector of maps to be selected
+static uint8_t find_map_read(struct vga_internal *vga, addr_t guest_addr)
 {
+    uint64_t mem_start, mem_end;
+    
+    mem_start=mem_end=0;
+    
+    get_mem_region(vga, &mem_start, &mem_end);
+    
+    if (!vga->vga_sequencer.vga_mem_mode.odd_even) { 
+      // odd-even mode
+      // last bit tells us map 0 or 1
+      return (guest_addr-mem_start) & 0x1; 
+    } 
 
-    if (vga->vga_sequencer.vga_mem_mode.chain4) { 
-       return !(new_guest_addr & 0x3);
-    } else {
-       return 1;
+    if (vga->vga_sequencer.vga_mem_mode.chain4) {
+      // otherwise chain4 if it's on
+      // last two bits
+      return (guest_addr - mem_start) & 0x3;
     }
+
+    // and what you would expect if neither are on
+    // note that it's not the same as a write!
+    return vga->vga_graphics_controller.vga_read_map_select.map_select;
+}
+
+static uint8_t find_increment_read(struct vga_internal *vga, addr_t new_guest_addr)
+{
+
+  if (!vga->vga_sequencer.vga_mem_mode.odd_even) { 
+    // odd-even mode
+    return !(new_guest_addr & 0x1); 
+  } 
+
+  if (vga->vga_sequencer.vga_mem_mode.chain4) { 
+    return !(new_guest_addr & 0x3);
+  } 
+  return 1;
 }
 
 
@@ -1528,7 +1574,8 @@ static int vga_read(struct guest_info * core,
     struct vga_internal *vga = (struct vga_internal *) dev->private_data;
     
 
-    PrintDebug("vga: memory read: guest_addr=0x%p len=%u\n",(void*)guest_addr, length);
+    PrintDebug("vga: memory read: guest_addr=0x%p len=%u read_mode=%d\n",(void*)guest_addr, length,
+              vga->vga_graphics_controller.vga_graphics_mode.read_mode);
 
         
    
@@ -1538,46 +1585,29 @@ static int vga_read(struct guest_info * core,
     switch (vga->vga_graphics_controller.vga_graphics_mode.read_mode) { 
        case 0: {
            /*      0 - a byte from ONE of the 4 planes is returned; 
-                   which plane is determined by Read Map Select (Read Map Select Register (Index 04h)) */
+                   which plane is determined by Read Map Select (Read Map Select Register (Index 04h))
+                   OR by odd/even chaining OR by chain4 chaining
+           */
            uint8_t  mapnum;
            uint64_t offset;
+           uint32_t i;
 
-
-           if (vga->vga_sequencer.vga_mem_mode.chain4) { 
-               uint32_t i;
-               offset = find_offset_read(vga,guest_addr);
-               // address bytes select the map
-               for (i=0;i<length;i++,offset+=find_increment_read(vga,guest_addr+i)) { 
-                   mapnum = (guest_addr+i) % 4;
+           offset = find_offset_read(vga,guest_addr);
+           
 #if DEBUG_DEEP_MEM
-                   PrintDebug("vga: mode 0 read, chain4, offset=0x%llx, mapnum=%u\n",offset,mapnum);
+           PrintDebug("vga: mode 0 read, offset=0x%llx\n",offset);
 #endif
-                   ((uint8_t*)dst)[i] = *(vga->map[mapnum]+offset);
+           for (i=0;i<length;i++,offset+=find_increment_read(vga,guest_addr+i)) { 
+
+             mapnum = find_map_read(vga,guest_addr+i);
+
+             ((uint8_t*)dst)[i] = *(vga->map[mapnum]+offset);
+             
+             vga->latch[mapnum] = *(vga->map[mapnum]+offset);
 
-                   // presumably all the latches are to be reloaded, not just the selected one?
-                   for (mapnum=0;mapnum<4;mapnum++) { 
-                       vga->latch[mapnum] = *(vga->map[mapnum]+offset);
-                   }
-               }
-           } else {
-               mapnum = vga->vga_graphics_controller.vga_read_map_select.map_select;
-               offset = find_offset_read(vga,guest_addr);
-               
-               if (offset>=65536) { 
-                   PrintError("vga: read to offset=%llu map=%u (%u bytes)\n",offset,mapnum,length);
-               }
-               
-#if DEBUG_DEEP_MEM
-               PrintDebug("vga: mode 0 read, not-chain4, offset=0x%llx, mapnum=%u\n",offset,mapnum);
-#endif
 
-               memcpy(dst,(vga->map[mapnum])+offset,length);
-               
-               // load the latches with the last item read
-               for (mapnum=0;mapnum<4;mapnum++) { 
-                   vga->latch[mapnum] = vga->map[mapnum][offset+length-1];
-               }
            }
+
        
        }
            break;
@@ -2645,9 +2675,10 @@ static int dac_pixel_mask_write(struct guest_info *core,
 
 static int init_vga(struct vga_internal *vga)
 {
-    // TODO: startup spec of register contents, if any
-    PrintError("vga: init_vga is UNIMPLEMTED\n");
-    return 0;
+  // TODO: startup spec of register contents, if any
+  vga->vga_misc.vga_input_stat1.val = 0x1;  // display enable, not in retrace
+
+  return 0;
 }
 
 static int free_vga(struct vga_internal *vga) 

diff --git a/palacios/src/devices/vga_regs.h b/palacios/src/devices/vga_regs.h
index 08b65f2..fd4a068 100644 (file)
--- a/palacios/src/devices/vga_regs.h
+++ b/palacios/src/devices/vga_regs.h
@@ -199,6 +199,7 @@ struct vga_mem_mode_reg {
            uint8_t extended_memory:1; // 1=>256K RAM, 0=>64K
            uint8_t odd_even:1;
                 // 0 => even addresses go to BOTH banks 0 and 2, odd 1 and 3
+               //      or flip between 0/1 for CGA compat
                 // 1 => address bank sequentially, map mask selects bank
            uint8_t chain4:1;  
                 // 0 => map mask register used to select bank
@@ -630,6 +631,8 @@ page 2-88).
            // 0 = read gets bits from selected map
            uint8_t odd_even:1;
            // 1 = odd/even addressing as in CGMA
+           // 0 = NOT odd/even
+           // notice that this is the OPPOSITE of the bit in the sequencer!
            uint8_t shift_reg_mode:1;
            // 1 = shift regs get odd bits from odd maps and even/even
            uint8_t c256:1;                 // 1 = 256 color mode