1 2 /* 3 NetWinder Floating Point Emulator 4 (c) Rebel.com, 1998-1999 5 (c) Philip Blundell, 1998-1999 6 7 Direct questions, comments to Scott Bambrough <scottb@netwinder.org> 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 2 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 22 */ 23 24 #include "fpa11.h" 25 26 #include <linux/module.h> 27 #include <linux/config.h> 28 29 /* XXX */ 30 #include <linux/errno.h> 31 #include <linux/types.h> 32 #include <linux/kernel.h> 33 #include <linux/signal.h> 34 #include <linux/sched.h> 35 #include <linux/init.h> 36 /* XXX */ 37 38 #include "softfloat.h" 39 #include "fpopcode.h" 40 #include "fpmodule.h" 41 #include "fpa11.inl" 42 43 /* kernel symbols required for signal handling */ 44 #ifdef CONFIG_FPE_NWFPE_XP 45 #define NWFPE_BITS "extended" 46 #else 47 #define NWFPE_BITS "double" 48 #endif 49 50 #ifdef MODULE 51 void fp_send_sig(unsigned long sig, struct task_struct *p, int priv); 52 #else 53 #define fp_send_sig send_sig 54 #define kern_fp_enter fp_enter 55 56 extern char fpe_type[]; 57 #endif 58 59 /* kernel function prototypes required */ 60 void fp_setup(void); 61 62 /* external declarations for saved kernel symbols */ 63 extern void (*kern_fp_enter)(void); 64 extern void (*fp_init)(union fp_state *); 65 66 /* Original value of fp_enter from kernel before patched by fpe_init. */ 67 static void (*orig_fp_enter)(void); 68 static void (*orig_fp_init)(union fp_state *); 69 70 /* forward declarations */ 71 extern void nwfpe_enter(void); 72 73 static int __init fpe_init(void) 74 { 75 if (sizeof(FPA11) > sizeof(union fp_state)) { 76 printk(KERN_ERR "nwfpe: bad structure size\n"); 77 return -EINVAL; 78 } 79 80 if (sizeof(FPREG) != 12) { 81 printk(KERN_ERR "nwfpe: bad register size\n"); 82 return -EINVAL; 83 } 84 if (fpe_type[0] && strcmp(fpe_type, "nwfpe")) 85 return 0; 86 87 /* Display title, version and copyright information. */ 88 printk(KERN_WARNING "NetWinder Floating Point Emulator V0.97 (" 89 NWFPE_BITS " precision)\n"); 90 91 /* Save pointer to the old FP handler and then patch ourselves in */ 92 orig_fp_enter = kern_fp_enter; 93 orig_fp_init = fp_init; 94 kern_fp_enter = nwfpe_enter; 95 fp_init = nwfpe_init_fpa; 96 97 return 0; 98 } 99 100 static void __exit fpe_exit(void) 101 { 102 /* Restore the values we saved earlier. */ 103 kern_fp_enter = orig_fp_enter; 104 fp_init = orig_fp_init; 105 } 106 107 /* 108 ScottB: November 4, 1998 109 110 Moved this function out of softfloat-specialize into fpmodule.c. 111 This effectively isolates all the changes required for integrating with the 112 Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying 113 fpmodule.c to integrate with the NetBSD kernel (I hope!). 114 115 [1/1/99: Not quite true any more unfortunately. There is Linux-specific 116 code to access data in user space in some other source files at the 117 moment (grep for get_user / put_user calls). --philb] 118 119 This function is called by the SoftFloat routines to raise a floating 120 point exception. We check the trap enable byte in the FPSR, and raise 121 a SIGFPE exception if necessary. If not the relevant bits in the 122 cumulative exceptions flag byte are set and we return. 123 */ 124 125 void float_raise(signed char flags) 126 { 127 register unsigned int fpsr, cumulativeTraps; 128 129 #ifdef CONFIG_DEBUG_USER 130 /* Ignore inexact errors as there are far too many of them to log */ 131 if (flags & ~BIT_IXC) 132 printk(KERN_DEBUG 133 "NWFPE: %s[%d] takes exception %08x at %p from %08lx\n", 134 current->comm, current->pid, flags, 135 __builtin_return_address(0), GET_USERREG()->ARM_pc); 136 #endif 137 138 /* Read fpsr and initialize the cumulativeTraps. */ 139 fpsr = readFPSR(); 140 cumulativeTraps = 0; 141 142 /* For each type of exception, the cumulative trap exception bit is only 143 set if the corresponding trap enable bit is not set. */ 144 if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC)) 145 cumulativeTraps |= BIT_IXC; 146 if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC)) 147 cumulativeTraps |= BIT_UFC; 148 if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC)) 149 cumulativeTraps |= BIT_OFC; 150 if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC)) 151 cumulativeTraps |= BIT_DZC; 152 if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC)) 153 cumulativeTraps |= BIT_IOC; 154 155 /* Set the cumulative exceptions flags. */ 156 if (cumulativeTraps) 157 writeFPSR(fpsr | cumulativeTraps); 158 159 /* Raise an exception if necessary. */ 160 if (fpsr & (flags << 16)) 161 fp_send_sig(SIGFPE, current, 1); 162 } 163 164 module_init(fpe_init); 165 module_exit(fpe_exit); 166 167 MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>"); 168 MODULE_DESCRIPTION("NWFPE floating point emulator (" NWFPE_BITS " precision)"); 169 MODULE_LICENSE("GPL"); 170