patch-2.1.97 linux/arch/ppc/kernel/softemu8xx.c

• Lines: 98
• Date: Tue Apr 14 17:33:58 1998
• Orig file: v2.1.96/linux/arch/ppc/kernel/softemu8xx.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.96/linux/arch/ppc/kernel/softemu8xx.c linux/arch/ppc/kernel/softemu8xx.c
@@ -0,0 +1,97 @@
+/*
+ * Software emulation of some PPC instructions for the 8xx core.
+ *
+ * Copyright (C) 1998 Dan Malek (dmalek@jlc.net)
+ *
+ * Software floating emuation for the MPC8xx processor.  I did this mostly
+ * because it was easier than trying to get the libraries compiled for
+ * software floating point.  The goal is still to get the libraries done,
+ * but I lost patience and needed some hacks to at least get init and
+ * shells running.  The first problem is the setjmp/longjmp that save
+ * and restore the floating point registers.
+ *
+ * For this emulation, our working registers are found on the register
+ * save area.
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/malloc.h>
+#include <linux/user.h>
+#include <linux/a.out.h>
+#include <linux/interrupt.h>
+#include <linux/config.h>
+
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+
+/* Eventually we may need a look-up table, but this works for now.
+*/
+#define LFD	50
+#define LFDU	51
+#define STFD	54
+#define STFDU	55
+
+/*
+ * We return 0 on success, 1 on unimplemented instruction, and EFAULT
+ * if a load/store faulted.
+ */
+int
+Soft_emulate_8xx(struct pt_regs *regs)
+{
+	uint	inst, instword;
+	uint	flreg, idxreg, disp;
+	uint	retval;
+	uint	*ea, *ip;
+
+	retval = 0;
+
+	instword = *((uint *)regs->nip);
+	inst = instword >> 26;
+
+	flreg = (instword >> 21) & 0x1f;
+	idxreg = (instword >> 16) & 0x1f;
+	disp = instword & 0xffff;
+
+	ea = (uint *)(regs->gpr[idxreg] + disp);
+	ip = (uint *)&current->tss.fpr[flreg];
+
+	if (inst == LFD) {
+		if (copy_from_user(ip, ea, sizeof(double)))
+			retval = EFAULT;
+	}
+	else if (inst == LFDU) {
+
+		if (copy_from_user(ip, ea, sizeof(double)))
+			retval = EFAULT;
+		else
+			regs->gpr[idxreg] = (uint)ea;
+	}
+	else if (inst == STFD) {
+
+		if (copy_to_user(ea, ip, sizeof(double)))
+			retval = EFAULT;
+	}
+	else if (inst == STFDU) {
+
+		if (copy_to_user(ea, ip, sizeof(double)))
+			retval = EFAULT;
+		else
+			regs->gpr[idxreg] = (uint)ea;
+	}
+	else {
+		retval = 1;
+	}
+
+	if (retval == 0)
+		regs->nip += 4;
+	return(retval);
+}