Enable cpu support for sse in bootstrap (#17)

* sse xorps instruction is emitted
* Fixes the triple exception boot error when a sse instruction is encountered

build/build.cmd

@@ -14,7 +14,7 @@ mkdir ..\bin
 cd ..\bin
 
 csc /debug:embedded /noconfig /nostdlib /runtimemetadataversion:v4.0.30319 ../src/PatienceOS.Kernel/kernel.cs ../src/PatienceOS.Kernel/Console.cs ../src/PatienceOS.Kernel/FrameBuffer.cs ../src/PatienceOS.Kernel/zerosharp.cs /out:kernel.ilexe /langversion:latest /unsafe || goto Error
-ilc --targetos windows --targetarch x86 kernel.ilexe -g -o kernel.obj --systemmodule kernel --map kernel.map -O || goto Error
+ilc --targetos windows --targetarch x86 --instruction-set base --verbose kernel.ilexe -g -o kernel.obj --systemmodule kernel --map kernel.map -O || goto Error
 nasm -f win32 -o loader.obj ../src/loader.asm || goto Error
 
 :: QEMU doesn't boot properly when I use the Microsoft linker, continually stuck in a BIOS loop looking for something to boot.
@@ -23,7 +23,7 @@ nasm -f win32 -o loader.obj ../src/loader.asm || goto Error
 
 ld -m i386pe -T ../src/linker.ld -o kernel.bin loader.obj kernel.obj || goto Error
 objcopy -O elf32-i386 kernel.bin kernel.elf || goto Error
-qemu-system-i386 -kernel kernel.elf || goto Error
+qemu-system-i386 -cpu pentium3 -kernel kernel.elf -d int -no-reboot -no-shutdown || goto Error
 
 cd ..\build
 exit /B

src/PatienceOS.Kernel/Console.cs

@@ -11,6 +11,7 @@ unsafe public struct Console
         private FrameBuffer frameBuffer;
 
         private int pos = 0;
+        private byte foregroundColor = 0x0F; // White
 
         public Console(int width, int height, FrameBuffer frameBuffer)
         {
@@ -40,7 +41,7 @@ public void Print(string s)
                 for (int i = 0; i < s.Length; i++)
                 {
                     frameBuffer.Write(pos, (byte)ps[i]);
-                    frameBuffer.Write(pos + 1, 0x0F);
+                    frameBuffer.Write(pos + 1, foregroundColor);
 
                     pos += 2;
                 }

src/loader.asm

@@ -19,9 +19,31 @@ section .text
     dd CHECKSUM
 
 _start:
-    cli                   ; block interrupts
+    cli                   ; block interrupts (nb. not necessary, as QEMU boots into 32-bit protected mode with interrupts disabled)
     mov esp, stack_space  ; set stack pointer
 
+
+enablesse:
+    ; Is SSE supported on this CPU?
+    mov eax, 0x1
+    cpuid
+    test edx, 1<<25
+    jnz .sse                   ; If SSE supported enable it.
+.nosse:
+    ; SSE not supported - do something like print an error and stop
+    jmp $
+
+.sse:
+    ;now enable SSE and the like
+    mov eax, cr0
+    and ax, 0xFFFB             ; clear coprocessor emulation CR0.EM
+    or ax, 0x2                 ; set coprocessor monitoring  CR0.MP
+    mov cr0, eax
+    mov eax, cr4
+    or ax, 3 << 9              ; set CR4.OSFXSR and CR4.OSXMMEXCPT at the same time
+    mov cr4, eax
+
+
     ; Call Main
     call __managed__Main