add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/x86/lib/mmx_32.c
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@@ -26,6 +26,16 @@
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 #include <asm/fpu/api.h>
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 #include <asm/asm.h>
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+/*
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+ * Use KFPU_387.  MMX instructions are not affected by MXCSR,
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+ * but both AMD and Intel documentation states that even integer MMX
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+ * operations will result in #MF if an exception is pending in FCW.
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+ *
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+ * EMMS is not needed afterwards because, after calling kernel_fpu_end(),
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+ * any subsequent user of the 387 stack will reinitialize it using
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+ * KFPU_387.
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+ */
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+
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 void *_mmx_memcpy(void *to, const void *from, size_t len)
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 {
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 	void *p;
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@@ -37,7 +47,7 @@
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 	p = to;
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 	i = len >> 6; /* len/64 */
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-	kernel_fpu_begin();
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+	kernel_fpu_begin_mask(KFPU_387);
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 	__asm__ __volatile__ (
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 		"1: prefetch (%0)\n"		/* This set is 28 bytes */
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@@ -127,7 +137,7 @@
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 {
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 	int i;
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-	kernel_fpu_begin();
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+	kernel_fpu_begin_mask(KFPU_387);
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 	__asm__ __volatile__ (
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 		"  pxor %%mm0, %%mm0\n" : :
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@@ -160,7 +170,7 @@
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 {
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 	int i;
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-	kernel_fpu_begin();
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+	kernel_fpu_begin_mask(KFPU_387);
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 	/*
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 	 * maybe the prefetch stuff can go before the expensive fnsave...
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@@ -247,7 +257,7 @@
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 {
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 	int i;
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-	kernel_fpu_begin();
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+	kernel_fpu_begin_mask(KFPU_387);
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 	__asm__ __volatile__ (
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 		"  pxor %%mm0, %%mm0\n" : :
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@@ -282,7 +292,7 @@
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 {
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 	int i;
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-	kernel_fpu_begin();
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+	kernel_fpu_begin_mask(KFPU_387);
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 	__asm__ __volatile__ (
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 		"1: prefetch (%0)\n"