patch-2.3.21 linux/arch/i386/lib/mmx.c

• Lines: 237
• Date: Mon Oct 11 10:06:34 1999
• Orig file: v2.3.20/linux/arch/i386/lib/mmx.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.20/linux/arch/i386/lib/mmx.c linux/arch/i386/lib/mmx.c
@@ -0,0 +1,236 @@
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+
+/*
+ *	MMX 3DNow! library helper functions
+ *
+ *	To do:
+ *	We can use MMX just for prefetch in IRQ's. This may be a win. 
+ *		(reported so on K6-III)
+ *	We should use a better code neutral filler for the short jump
+ *		leal ebx. [ebx] is apparently best for K6-2, but Cyrix ??
+ *	We also want to clobber the filler register so we dont get any
+ *		register forwarding stalls on the filler. 
+ *
+ *	Add *user handling. Checksums are not a win with MMX on any CPU
+ *	tested so far for any MMX solution figured.
+ *
+ */
+ 
+void *_mmx_memcpy(void *to, const void *from, size_t len)
+{
+	void *p=to;
+	int i= len >> 6;	/* len/64 */
+
+	if (!(current->flags & PF_USEDFPU))
+		clts();
+	else
+	{
+		__asm__ __volatile__ ( " fnsave %0; fwait\n"::"m"(current->thread.i387));
+		current->flags &= ~PF_USEDFPU;
+	}
+
+	__asm__ __volatile__ (
+		"1: prefetch (%0)\n"		/* This set is 28 bytes */
+		"   prefetch 64(%0)\n"
+		"   prefetch 128(%0)\n"
+		"   prefetch 192(%0)\n"
+		"   prefetch 256(%0)\n"
+		"2:  \n"
+		".section .fixup, \"ax\"\n"
+		"3: movw $0x1AEB, 1b\n"	/* jmp on 26 bytes */
+		"   jmp 2b\n"
+		".previous\n"
+		".section __ex_table,\"a\"\n"
+		"	.align 4\n"
+		"	.long 1b, 3b\n"
+		".previous"
+		: : "r" (from) );
+		
+	
+	for(; i>0; i--)
+	{
+		__asm__ __volatile__ (
+		"1:  prefetch 320(%0)\n"
+		"2:  movq (%0), %%mm0\n"
+		"  movq 8(%0), %%mm1\n"
+		"  movq 16(%0), %%mm2\n"
+		"  movq 24(%0), %%mm3\n"
+		"  movq %%mm0, (%1)\n"
+		"  movq %%mm1, 8(%1)\n"
+		"  movq %%mm2, 16(%1)\n"
+		"  movq %%mm3, 24(%1)\n"
+		"  movq 32(%0), %%mm0\n"
+		"  movq 40(%0), %%mm1\n"
+		"  movq 48(%0), %%mm2\n"
+		"  movq 56(%0), %%mm3\n"
+		"  movq %%mm0, 32(%1)\n"
+		"  movq %%mm1, 40(%1)\n"
+		"  movq %%mm2, 48(%1)\n"
+		"  movq %%mm3, 56(%1)\n"
+		".section .fixup, \"ax\"\n"
+		"3: movw $0x05EB, 1b\n"	/* jmp on 5 bytes */
+		"   jmp 2b\n"
+		".previous\n"
+		".section __ex_table,\"a\"\n"
+		"	.align 4\n"
+		"	.long 1b, 3b\n"
+		".previous"
+		: : "r" (from), "r" (to) : "memory");
+		from+=64;
+		to+=64;
+	}
+	/*
+	 *	Now do the tail of the block
+	 */
+	__memcpy(to, from, len&63);
+	stts();
+	return p;
+}
+
+static void fast_clear_page(long page)
+{
+	int i;
+	if (!(current->flags & PF_USEDFPU))
+		clts();
+	else
+	{
+		__asm__ __volatile__ ( " fnsave %0; fwait\n"::"m"(current->thread.i387));
+		current->flags &= ~PF_USEDFPU;
+	}
+	
+	__asm__ __volatile__ (
+		"  pxor %%mm0, %%mm0\n" : :
+	);
+
+	for(i=0;i<4096/128;i++)
+	{
+		__asm__ __volatile__ (
+		"  movq %%mm0, (%0)\n"
+		"  movq %%mm0, 8(%0)\n"
+		"  movq %%mm0, 16(%0)\n"
+		"  movq %%mm0, 24(%0)\n"
+		"  movq %%mm0, 32(%0)\n"
+		"  movq %%mm0, 40(%0)\n"
+		"  movq %%mm0, 48(%0)\n"
+		"  movq %%mm0, 56(%0)\n"
+		"  movq %%mm0, 64(%0)\n"
+		"  movq %%mm0, 72(%0)\n"
+		"  movq %%mm0, 80(%0)\n"
+		"  movq %%mm0, 88(%0)\n"
+		"  movq %%mm0, 96(%0)\n"
+		"  movq %%mm0, 104(%0)\n"
+		"  movq %%mm0, 112(%0)\n"
+		"  movq %%mm0, 120(%0)\n"
+		: : "r" (page) : "memory");
+		page+=128;
+	}
+	stts();
+}
+
+static void fast_copy_page(long to, long from)
+{
+	int i;
+	if (!(current->flags & PF_USEDFPU))
+		clts();
+	else
+	{
+		__asm__ __volatile__ ( " fnsave %0; fwait\n"::"m"(current->thread.i387));
+		current->flags &= ~PF_USEDFPU;
+	}
+
+	__asm__ __volatile__ (
+		"1: prefetch (%0)\n"
+		"   prefetch 64(%0)\n"
+		"   prefetch 128(%0)\n"
+		"   prefetch 192(%0)\n"
+		"   prefetch 256(%0)\n"
+		"2:  \n"
+		".section .fixup, \"ax\"\n"
+		"3: movw $0x1AEB, 1b\n"	/* jmp on 26 bytes */
+		"   jmp 2b\n"
+		".previous\n"
+		".section __ex_table,\"a\"\n"
+		"	.align 4\n"
+		"	.long 1b, 3b\n"
+		".previous"
+		: : "r" (from) );
+
+	for(i=0; i<4096/64; i++)
+	{
+		__asm__ __volatile__ (
+		"1: prefetch 320(%0)\n"
+		"2: movq (%0), %%mm0\n"
+		"   movq 8(%0), %%mm1\n"
+		"   movq 16(%0), %%mm2\n"
+		"   movq 24(%0), %%mm3\n"
+		"   movq %%mm0, (%1)\n"
+		"   movq %%mm1, 8(%1)\n"
+		"   movq %%mm2, 16(%1)\n"
+		"   movq %%mm3, 24(%1)\n"
+		"   movq 32(%0), %%mm0\n"
+		"   movq 40(%0), %%mm1\n"
+		"   movq 48(%0), %%mm2\n"
+		"   movq 56(%0), %%mm3\n"
+		"   movq %%mm0, 32(%1)\n"
+		"   movq %%mm1, 40(%1)\n"
+		"   movq %%mm2, 48(%1)\n"
+		"   movq %%mm3, 56(%1)\n"
+		".section .fixup, \"ax\"\n"
+		"3: movw $0x05EB, 1b\n"	/* jmp on 5 bytes */
+		"   jmp 2b\n"
+		".previous\n"
+		".section __ex_table,\"a\"\n"
+		"	.align 4\n"
+		"	.long 1b, 3b\n"
+		".previous"
+		: : "r" (from), "r" (to) : "memory");
+		from+=64;
+		to+=64;
+	}
+	stts();
+}
+
+/*
+ *	Favour MMX for page clear and copy. 
+ */
+
+static void slow_zero_page(long page)
+{
+	int d0, d1;
+	__asm__ __volatile__( \
+		"cld\n\t" \
+		"rep ; stosl" \
+		: "=&c" (d0), "=&D" (d1)
+		:"a" (0),"1" (page),"0" (1024)
+		:"memory");
+}
+ 
+void mmx_clear_page(long page)
+{
+	if(in_interrupt())
+		slow_zero_page(page);
+	else
+		fast_clear_page(page);
+}
+
+static void slow_copy_page(long to, long from)
+{
+	int d0, d1, d2;
+	__asm__ __volatile__( \
+		"cld\n\t" \
+		"rep ; movsl" \
+		: "=&c" (d0), "=&D" (d1), "=&S" (d2) \
+		: "0" (1024),"1" ((long) to),"2" ((long) from) \
+		: "memory");
+}
+  
+
+void mmx_copy_page(long to, long from)
+{
+	if(in_interrupt())
+		slow_copy_page(to, from);
+	else
+		fast_copy_page(to, from);
+}