2009-11-10 Till Straumann <strauman@slac.stanford.edu>

* pc386/make/custom/pc586-sse.cfg, pc386/start/start.S,
	shared/irq/irq_asm.S: Added experimental SSE support.

c/src/lib/libbsp/i386/ChangeLog

@@ -1,3 +1,8 @@
+2009-11-10	Till Straumann <strauman@slac.stanford.edu>
+
+	* pc386/make/custom/pc586-sse.cfg, pc386/start/start.S,
+	shared/irq/irq_asm.S: Added experimental SSE support.
+
 2009-10-29	Till Straumann <strauman@slac.stanford.edu>
 
 	* shared/irq/irq_asm.S: Make sure stack is aligned to CPU_STACK_ALIGNMENT

c/src/lib/libbsp/i386/pc386/make/custom/pc586-sse.cfg

@@ -0,0 +1,37 @@
+#
+#  Configuration file for a PC using a Pentium Class CPU
+#
+#  $Id$
+#
+
+RTEMS_CPU_MODEL=pentium
+
+#  This contains the compiler options necessary to select the CPU model
+#  and enable architecture-specific features and extensions.
+
+#  Note that the vanilla gcc multilibs for RTEMS are a joke. The
+#  variants only differ by a -mtune=xxx option which merely 'optimizes'
+#  for 'xxx' but does not use the full instruction set 'xxx' may implement.
+#  (fully bwd compatible with i386).
+#
+#  I'd recommend to roll your own set of (useful) multilibs instead...
+#
+#  Useful variants would be
+#    <default> (i386) (generic 386 with hard-float)
+#    -msoft-float     (generic 386 with soft-float)
+#    -march=pentium4  (P4 with sse2)
+#
+#  Note also: we give the -mtune=pentium option here only so that at least the
+#             variant optimized for pentium (w/o using any pentium-specific
+#             features) is used (assuming you use the vanilla RTEMS multilibs).
+#  
+#  And: The only sse-related feature the RTEMS support really needs is
+#             fxsave/fxrstor. You can build with -msse, -msse2 or -msse3,
+#             depending on your CPU.
+#             There are run-time checks resulting in a 'panic' if code
+#             compiled for e.g. -msse3 is executed on a CPU that only
+#             supports sse2, though.
+CPU_CFLAGS = -mtune=pentium -march=pentium -msse2
+
+include $(RTEMS_ROOT)/make/custom/pc386.cfg
+

c/src/lib/libbsp/i386/pc386/start/start.S

@@ -69,6 +69,13 @@ BEGIN_CODE
 	EXTERN (debugPollingGetChar)
 	EXTERN (checkCPUtypeSetCr0)
 	EXTERN (BSP_console_select)
+	EXTERN (printk)
+#ifdef __SSE__
+	EXTERN (x86_capability)
+#ifdef __SSE3__
+	EXTERN (x86_capability_x)
+#endif
+#endif
 
 /*
  * In case this crashes on your machine and this is not due
@@ -142,7 +149,7 @@ speakl:	jmp	speakl             # and SPIN!!!
 	/*
 	 * try printk and a getchar in polling mode ASAP
 	 */
-	pushl	$welcome_msg
+	movl	$welcome_msg, 0(esp)
 	call	printk
 	addl	$4, esp
 
@@ -207,6 +214,44 @@ SYM (zero_bss):
 +---------------------------------------------------------------------*/
 	call SYM(BSP_console_select)
 
+#ifdef __SSE__
+/*--------------------------------------------------------------------+
+ | Enable SSE; we really only care about fxsave/fxrstor and leave
+ | The only feature *we* (as an OS) use is fxsave/fxrstor.
+ | But as a courtesy we make sure we don't execute on hardware
+ | that doesn't support features possibly used by the compiler.
++---------------------------------------------------------------------*/
+	movl	SYM (x86_capability), eax
+	testl   $0x01000000, eax
+	jne     1f
+	movl    $SYM (no_fxsave_msg), 0(esp)
+	jmp     SYM(_sse_panic)
+1:
+	testl   $0x02000000, eax
+	jne     1f
+	movl    $SYM (no_sse_msg), 0(esp)
+	jmp     SYM(_sse_panic)
+1:	
+#ifdef __SSE2__
+	testl   $0x04000000, eax
+	jne     1f
+	movl    $SYM (no_sse2_msg), 0(esp)
+	jmp     SYM(_sse_panic)
+1:
+#endif
+#ifdef __SSE3__
+	movl	SYM (x86_capability_x), eax
+	testl   $1, eax
+	jne     1f
+	movl    $SYM (no_sse3_msg), 0(esp)
+	jmp     SYM(_sse_panic)
+1:
+#endif
+	mov     cr4, eax		# OK to enable now
+	or      $0x600, eax
+	mov     eax, cr4
+#endif
+
 /*---------------------------------------------------------------------+
 | Transfer control to User's Board Support Package
 | Note: at the top we reserved space for the argument
@@ -228,6 +273,13 @@ SYM (zero_bss):
 
 	jmp	SYM (_return_to_monitor)
 
+#ifdef __SSE__
+SYM(_sse_panic):
+	call SYM(printk)
+1:	hlt
+	jmp 1b
+#endif
+
 END_CODE
 
 BEGIN_DATA
@@ -270,6 +322,21 @@ SYM (made_it_msg) :
 
 #endif
 
+#ifdef __SSE__
+SYM (no_fxsave_msg) :
+	.string "PANIC: compiled for SSE but CPU seems to have no FXSAVE/FXRSTOR support (which I need)\n"
+SYM (no_sse_msg) :
+	.string "PANIC: compiled for SSE but your CPU seems to have no SSE support\n"
+#ifdef __SSE2__
+SYM (no_sse2_msg) :
+	.string "PANIC: compiled for SSE2 but your CPU seems to have no SSE2 support\n"
+#endif
+#ifdef __SSE3__
+SYM (no_sse3_msg) :
+	.string "PANIC: compiled for SSE3 but your CPU seems to have no SSE3 support\n"
+#endif
+#endif
+
 END_DATA
 
 END

c/src/lib/libbsp/i386/shared/irq/irq_asm.S

@@ -24,7 +24,12 @@
 #define MSK_OFF 4
 #define EBP_OFF 8        /* code restoring ebp/esp relies on */
 #define ESP_OFF 12       /* esp being on top of ebp!         */
+#ifdef __SSE__
+#define FRM_SIZ (16+512)
+#define SSE_OFF 16
+#else
 #define FRM_SIZ 16 
+#endif
 
 	BEGIN_CODE
 
@@ -70,6 +75,27 @@ SYM (_ISR_Handler):
 	movl      eax, ESP_OFF(esp)
 	movl      ebp, EBP_OFF(esp)
 
+#ifdef __SSE__
+	/* NOTE: SSE only is supported if the BSP enables fxsave/fxrstor
+	 * to save/restore SSE context! This is so far only implemented
+	 * for pc386!.
+	 */
+
+	/* We save SSE here (on the task stack) because we possibly
+	 * call other C-code (besides the ISR, namely _Thread_Dispatch()
+	 * or _ThreadProcessSignalsFromIrq()).
+	 */
+    /*  don't wait here; a possible exception condition will eventually be
+     *  detected when the task resumes control and executes a FP instruction
+	fwait
+     */
+	fxsave SSE_OFF(esp)
+	fninit                          /* clean-slate FPU                */
+	movl   $0x1f80, ARG_OFF(esp)	/* use ARG_OFF as scratch space   */
+	ldmxcsr ARG_OFF(esp)            /* clean-slate MXCSR              */
+#endif
+
+
 	/*
 	 * acknowledge the interrupt
 	 *
@@ -197,6 +223,12 @@ nested:
 	 * eip, CS, Flags).
 	 */
 .exit:
+
+#ifdef __SSE__
+	fwait
+	fxrstor   SSE_OFF(esp)
+#endif
+
 	/* restore ebp and original esp */
 	addl      $EBP_OFF, esp
 	popl      ebp