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Diffstat (limited to 'arch/arm26/nwfpe/fpmodule.c')
| -rw-r--r-- | arch/arm26/nwfpe/fpmodule.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/arch/arm26/nwfpe/fpmodule.c b/arch/arm26/nwfpe/fpmodule.c new file mode 100644 index 00000000000..528fa710aa3 --- /dev/null +++ b/arch/arm26/nwfpe/fpmodule.c @@ -0,0 +1,182 @@ + +/* + NetWinder Floating Point Emulator + (c) Rebel.com, 1998-1999 + (c) Philip Blundell, 1998-1999 + + Direct questions, comments to Scott Bambrough <scottb@netwinder.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "fpa11.h" + +#include <linux/module.h> +#include <linux/version.h> +#include <linux/config.h> + +/* XXX */ +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/signal.h> +#include <linux/sched.h> +#include <linux/init.h> +/* XXX */ + +#include "softfloat.h" +#include "fpopcode.h" +#include "fpmodule.h" +#include "fpa11.inl" + +/* kernel symbols required for signal handling */ +typedef struct task_struct* PTASK; + +#ifdef MODULE +void fp_send_sig(unsigned long sig, PTASK p, int priv); +#if LINUX_VERSION_CODE > 0x20115 +MODULE_AUTHOR("Scott Bambrough <scottb@rebel.com>"); +MODULE_DESCRIPTION("NWFPE floating point emulator"); +#endif + +#else +#define fp_send_sig send_sig +#define kern_fp_enter fp_enter + +extern char fpe_type[]; +#endif + +/* kernel function prototypes required */ +void fp_setup(void); + +/* external declarations for saved kernel symbols */ +extern void (*kern_fp_enter)(void); + +/* Original value of fp_enter from kernel before patched by fpe_init. */ +static void (*orig_fp_enter)(void); + +/* forward declarations */ +extern void nwfpe_enter(void); + +#ifdef MODULE +/* + * Return 0 if we can be unloaded. This can only happen if + * kern_fp_enter is still pointing at nwfpe_enter + */ +static int fpe_unload(void) +{ + return (kern_fp_enter == nwfpe_enter) ? 0 : 1; +} +#endif + +static int __init fpe_init(void) +{ + if (sizeof(FPA11) > sizeof(union fp_state)) { + printk(KERN_ERR "nwfpe: bad structure size\n"); + return -EINVAL; + } + + if (sizeof(FPREG) != 12) { + printk(KERN_ERR "nwfpe: bad register size\n"); + return -EINVAL; + } + +#ifdef MODULE + if (!mod_member_present(&__this_module, can_unload)) + return -EINVAL; + __this_module.can_unload = fpe_unload; +#else + if (fpe_type[0] && strcmp(fpe_type, "nwfpe")) + return 0; +#endif + + /* Display title, version and copyright information. */ + printk(KERN_WARNING "NetWinder Floating Point Emulator V0.95 " + "(c) 1998-1999 Rebel.com\n"); + + /* Save pointer to the old FP handler and then patch ourselves in */ + orig_fp_enter = kern_fp_enter; + kern_fp_enter = nwfpe_enter; + + return 0; +} + +static void __exit fpe_exit(void) +{ + /* Restore the values we saved earlier. */ + kern_fp_enter = orig_fp_enter; +} + +/* +ScottB: November 4, 1998 + +Moved this function out of softfloat-specialize into fpmodule.c. +This effectively isolates all the changes required for integrating with the +Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying +fpmodule.c to integrate with the NetBSD kernel (I hope!). + +[1/1/99: Not quite true any more unfortunately. There is Linux-specific +code to access data in user space in some other source files at the +moment (grep for get_user / put_user calls). --philb] + +float_exception_flags is a global variable in SoftFloat. + +This function is called by the SoftFloat routines to raise a floating +point exception. We check the trap enable byte in the FPSR, and raise +a SIGFPE exception if necessary. If not the relevant bits in the +cumulative exceptions flag byte are set and we return. +*/ + +void float_raise(signed char flags) +{ + register unsigned int fpsr, cumulativeTraps; + +#ifdef CONFIG_DEBUG_USER + printk(KERN_DEBUG "NWFPE: %s[%d] takes exception %08x at %p from %08x\n", + current->comm, current->pid, flags, + __builtin_return_address(0), GET_USERREG()[15]); +#endif + + /* Keep SoftFloat exception flags up to date. */ + float_exception_flags |= flags; + + /* Read fpsr and initialize the cumulativeTraps. */ + fpsr = readFPSR(); + cumulativeTraps = 0; + + /* For each type of exception, the cumulative trap exception bit is only + set if the corresponding trap enable bit is not set. */ + if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC)) + cumulativeTraps |= BIT_IXC; + if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC)) + cumulativeTraps |= BIT_UFC; + if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC)) + cumulativeTraps |= BIT_OFC; + if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC)) + cumulativeTraps |= BIT_DZC; + if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC)) + cumulativeTraps |= BIT_IOC; + + /* Set the cumulative exceptions flags. */ + if (cumulativeTraps) + writeFPSR(fpsr | cumulativeTraps); + + /* Raise an exception if necessary. */ + if (fpsr & (flags << 16)) + fp_send_sig(SIGFPE, current, 1); +} + +module_init(fpe_init); +module_exit(fpe_exit); |