2 * linux/arch/unicore32/kernel/fpu-ucf64.c
4 * Code specific to PKUnity SoC and UniCore ISA
6 * Copyright (C) 2001-2010 GUAN Xue-tao
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/signal.h>
16 #include <linux/sched/signal.h>
17 #include <linux/init.h>
19 #include <asm/fpu-ucf64.h>
22 * A special flag to tell the normalisation code not to normalise.
24 #define F64_NAN_FLAG 0x100
27 * A bit pattern used to indicate the initial (unset) value of the
28 * exception mask, in case nothing handles an instruction. This
29 * doesn't include the NAN flag, which get masked out before
30 * we check for an error.
32 #define F64_EXCEPTION_ERROR ((u32)-1 & ~F64_NAN_FLAG)
35 * Since we aren't building with -mfpu=f64, we need to code
36 * these instructions using their MRC/MCR equivalents.
38 #define f64reg(_f64_) #_f64_
40 #define cff(_f64_) ({ \
42 asm("cff %0, " f64reg(_f64_) "@ fmrx %0, " #_f64_ \
43 : "=r" (__v) : : "cc"); \
47 #define ctf(_f64_, _var_) \
48 asm("ctf %0, " f64reg(_f64_) "@ fmxr " #_f64_ ", %0" \
49 : : "r" (_var_) : "cc")
52 * Raise a SIGFPE for the current process.
53 * sicode describes the signal being raised.
55 void ucf64_raise_sigfpe(struct pt_regs *regs)
58 * This is the same as NWFPE, because it's not clear what
61 current->thread.error_code = 0;
62 current->thread.trap_no = 6;
64 send_sig_fault(SIGFPE, FPE_FLTUNK,
65 (void __user *)(instruction_pointer(regs) - 4),
70 * Handle exceptions of UniCore-F64.
72 void ucf64_exchandler(u32 inst, u32 fpexc, struct pt_regs *regs)
75 u32 exc = F64_EXCEPTION_ERROR & fpexc;
77 pr_debug("UniCore-F64: instruction %08x fpscr %08x\n",
80 if (exc & FPSCR_CMPINSTR_BIT) {
85 exc &= ~(FPSCR_CMPINSTR_BIT | FPSCR_CON);
87 pr_debug("UniCore-F64 Error: unhandled exceptions\n");
88 pr_debug("UniCore-F64 FPSCR 0x%08x INST 0x%08x\n",
91 ucf64_raise_sigfpe(regs);
96 * Update the FPSCR with the additional exception flags.
97 * Comparison instructions always return at least one of
100 tmp &= ~(FPSCR_TRAP | FPSCR_IOS | FPSCR_OFS | FPSCR_UFS |
101 FPSCR_IXS | FPSCR_HIS | FPSCR_IOC | FPSCR_OFC |
102 FPSCR_UFC | FPSCR_IXC | FPSCR_HIC);
109 * F64 support code initialisation.
111 static int __init ucf64_init(void)
113 ctf(FPSCR, 0x0); /* FPSCR_UFE | FPSCR_NDE perhaps better */
115 printk(KERN_INFO "Enable UniCore-F64 support.\n");
120 late_initcall(ucf64_init);