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Diffstat (limited to 'arch/arm26/nwfpe/entry.S')
| -rw-r--r-- | arch/arm26/nwfpe/entry.S | 114 |
1 files changed, 0 insertions, 114 deletions
diff --git a/arch/arm26/nwfpe/entry.S b/arch/arm26/nwfpe/entry.S deleted file mode 100644 index e6312000d9f..00000000000 --- a/arch/arm26/nwfpe/entry.S +++ /dev/null @@ -1,114 +0,0 @@ -/* - NetWinder Floating Point Emulator - (c) Rebel.COM, 1998 - (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 <asm/asm-offsets.h> - -/* This is the kernel's entry point into the floating point emulator. -It is called from the kernel with code similar to this: - - mov fp, #0 - teqp pc, #PSR_I_BIT | MODE_SVC - ldr r4, .LC2 - ldr pc, [r4] @ Call FP module USR entry point - -The kernel expects the emulator to return via one of two possible -points of return it passes to the emulator. The emulator, if -successful in its emulation, jumps to ret_from_exception and the -kernel takes care of returning control from the trap to the user code. -If the emulator is unable to emulate the instruction, it returns to -fpundefinstr and the kernel halts the user program with a core dump. - -This routine does four things: - -1) It saves SP into a variable called userRegisters. The kernel has -created a struct pt_regs on the stack and saved the user registers -into it. See /usr/include/asm/proc/ptrace.h for details. The -emulator code uses userRegisters as the base of an array of words from -which the contents of the registers can be extracted. - -2) It locates the FP emulator work area within the TSS structure and -points `fpa11' to it. - -3) It calls EmulateAll to emulate a floating point instruction. -EmulateAll returns 1 if the emulation was successful, or 0 if not. - -4) If an instruction has been emulated successfully, it looks ahead at -the next instruction. If it is a floating point instruction, it -executes the instruction, without returning to user space. In this -way it repeatedly looks ahead and executes floating point instructions -until it encounters a non floating point instruction, at which time it -returns via _fpreturn. - -This is done to reduce the effect of the trap overhead on each -floating point instructions. GCC attempts to group floating point -instructions to allow the emulator to spread the cost of the trap over -several floating point instructions. */ - - .globl nwfpe_enter -nwfpe_enter: - mov sl, sp - bl FPA11_CheckInit @ check to see if we are initialised - - ldr r5, [sp, #60] @ get contents of PC - bic r5, r5, #0xfc000003 - ldr r0, [r5, #-4] @ get actual instruction into r0 - bl EmulateAll @ emulate the instruction -1: cmp r0, #0 @ was emulation successful - beq fpundefinstr @ no, return failure - -next: -.Lx1: ldrt r6, [r5], #4 @ get the next instruction and - @ increment PC - - and r2, r6, #0x0F000000 @ test for FP insns - teq r2, #0x0C000000 - teqne r2, #0x0D000000 - teqne r2, #0x0E000000 - bne ret_from_exception @ return ok if not a fp insn - - ldr r9, [sp, #60] @ get new condition codes - and r9, r9, #0xfc000003 - orr r7, r5, r9 - str r7, [sp, #60] @ update PC copy in regs - - mov r0, r6 @ save a copy - mov r1, r9 @ fetch the condition codes - bl checkCondition @ check the condition - cmp r0, #0 @ r0 = 0 ==> condition failed - - @ if condition code failed to match, next insn - beq next @ get the next instruction; - - mov r0, r6 @ prepare for EmulateAll() - adr lr, 1b - orr lr, lr, #3 - b EmulateAll @ if r0 != 0, goto EmulateAll - -.Lret: b ret_from_exception @ let the user eat segfaults - - @ We need to be prepared for the instruction at .Lx1 to fault. - @ Emit the appropriate exception gunk to fix things up. - .section __ex_table,"a" - .align 3 - .long .Lx1 - ldr lr, [lr, $(.Lret - .Lx1)/4] - .previous |