diff options
Diffstat (limited to 'drivers/FPU-emu/div_Xsig.S')
| -rw-r--r-- | drivers/FPU-emu/div_Xsig.S | 369 |
1 files changed, 0 insertions, 369 deletions
diff --git a/drivers/FPU-emu/div_Xsig.S b/drivers/FPU-emu/div_Xsig.S deleted file mode 100644 index 67d8be964..000000000 --- a/drivers/FPU-emu/div_Xsig.S +++ /dev/null @@ -1,369 +0,0 @@ - .file "div_Xsig.S" -/*---------------------------------------------------------------------------+ - | div_Xsig.S | - | | - | Division subroutine for 96 bit quantities | - | | - | Copyright (C) 1994 | - | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | - | Australia. E-mail billm@vaxc.cc.monash.edu.au | - | | - | | - +---------------------------------------------------------------------------*/ - -/*---------------------------------------------------------------------------+ - | Divide the 96 bit quantity pointed to by a, by that pointed to by b, and | - | put the 96 bit result at the location d. | - | | - | The result may not be accurate to 96 bits. It is intended for use where | - | a result better than 64 bits is required. The result should usually be | - | good to at least 94 bits. | - | The returned result is actually divided by one half. This is done to | - | prevent overflow. | - | | - | .aaaaaaaaaaaaaa / .bbbbbbbbbbbbb -> .dddddddddddd | - | | - | void div_Xsig(Xsig *a, Xsig *b, Xsig *dest) | - | | - +---------------------------------------------------------------------------*/ - -#include "exception.h" -#include "fpu_asm.h" - - -#define XsigLL(x) (x) -#define XsigL(x) 4(x) -#define XsigH(x) 8(x) - - -#ifndef NON_REENTRANT_FPU -/* - Local storage on the stack: - Accumulator: FPU_accum_3:FPU_accum_2:FPU_accum_1:FPU_accum_0 - */ -#define FPU_accum_3 -4(%ebp) -#define FPU_accum_2 -8(%ebp) -#define FPU_accum_1 -12(%ebp) -#define FPU_accum_0 -16(%ebp) -#define FPU_result_3 -20(%ebp) -#define FPU_result_2 -24(%ebp) -#define FPU_result_1 -28(%ebp) - -#else -.data -/* - Local storage in a static area: - Accumulator: FPU_accum_3:FPU_accum_2:FPU_accum_1:FPU_accum_0 - */ - .align 2,0 -FPU_accum_3: - .long 0 -FPU_accum_2: - .long 0 -FPU_accum_1: - .long 0 -FPU_accum_0: - .long 0 -FPU_result_3: - .long 0 -FPU_result_2: - .long 0 -FPU_result_1: - .long 0 -#endif NON_REENTRANT_FPU - - -.text - .align 2,144 - -.globl _div_Xsig - -_div_Xsig: - pushl %ebp - movl %esp,%ebp -#ifndef NON_REENTRANT_FPU - subl $28,%esp -#endif NON_REENTRANT_FPU - - pushl %esi - pushl %edi - pushl %ebx - - movl PARAM1,%esi /* pointer to num */ - movl PARAM2,%ebx /* pointer to denom */ - -#ifdef PARANOID - testl $0x80000000, XsigH(%ebx) /* Divisor */ - je L_bugged -#endif PARANOID - - -/*---------------------------------------------------------------------------+ - | Divide: Return arg1/arg2 to arg3. | - | | - | The maximum returned value is (ignoring exponents) | - | .ffffffff ffffffff | - | ------------------ = 1.ffffffff fffffffe | - | .80000000 00000000 | - | and the minimum is | - | .80000000 00000000 | - | ------------------ = .80000000 00000001 (rounded) | - | .ffffffff ffffffff | - | | - +---------------------------------------------------------------------------*/ - - /* Save extended dividend in local register */ - - /* Divide by 2 to prevent overflow */ - clc - movl XsigH(%esi),%eax - rcrl %eax - movl %eax,FPU_accum_3 - movl XsigL(%esi),%eax - rcrl %eax - movl %eax,FPU_accum_2 - movl XsigLL(%esi),%eax - rcrl %eax - movl %eax,FPU_accum_1 - movl $0,%eax - rcrl %eax - movl %eax,FPU_accum_0 - - movl FPU_accum_2,%eax /* Get the current num */ - movl FPU_accum_3,%edx - -/*----------------------------------------------------------------------*/ -/* Initialization done. - Do the first 32 bits. */ - - /* We will divide by a number which is too large */ - movl XsigH(%ebx),%ecx - addl $1,%ecx - jnc LFirst_div_not_1 - - /* here we need to divide by 100000000h, - i.e., no division at all.. */ - mov %edx,%eax - jmp LFirst_div_done - -LFirst_div_not_1: - divl %ecx /* Divide the numerator by the augmented - denom ms dw */ - -LFirst_div_done: - movl %eax,FPU_result_3 /* Put the result in the answer */ - - mull XsigH(%ebx) /* mul by the ms dw of the denom */ - - subl %eax,FPU_accum_2 /* Subtract from the num local reg */ - sbbl %edx,FPU_accum_3 - - movl FPU_result_3,%eax /* Get the result back */ - mull XsigL(%ebx) /* now mul the ls dw of the denom */ - - subl %eax,FPU_accum_1 /* Subtract from the num local reg */ - sbbl %edx,FPU_accum_2 - sbbl $0,FPU_accum_3 - je LDo_2nd_32_bits /* Must check for non-zero result here */ - -#ifdef PARANOID - jb L_bugged_1 -#endif PARANOID - - /* need to subtract another once of the denom */ - incl FPU_result_3 /* Correct the answer */ - - movl XsigL(%ebx),%eax - movl XsigH(%ebx),%edx - subl %eax,FPU_accum_1 /* Subtract from the num local reg */ - sbbl %edx,FPU_accum_2 - -#ifdef PARANOID - sbbl $0,FPU_accum_3 - jne L_bugged_1 /* Must check for non-zero result here */ -#endif PARANOID - -/*----------------------------------------------------------------------*/ -/* Half of the main problem is done, there is just a reduced numerator - to handle now. - Work with the second 32 bits, FPU_accum_0 not used from now on */ -LDo_2nd_32_bits: - movl FPU_accum_2,%edx /* get the reduced num */ - movl FPU_accum_1,%eax - - /* need to check for possible subsequent overflow */ - cmpl XsigH(%ebx),%edx - jb LDo_2nd_div - ja LPrevent_2nd_overflow - - cmpl XsigL(%ebx),%eax - jb LDo_2nd_div - -LPrevent_2nd_overflow: -/* The numerator is greater or equal, would cause overflow */ - /* prevent overflow */ - subl XsigL(%ebx),%eax - sbbl XsigH(%ebx),%edx - movl %edx,FPU_accum_2 - movl %eax,FPU_accum_1 - - incl FPU_result_3 /* Reflect the subtraction in the answer */ - -#ifdef PARANOID - je L_bugged_2 /* Can't bump the result to 1.0 */ -#endif PARANOID - -LDo_2nd_div: - cmpl $0,%ecx /* augmented denom msw */ - jnz LSecond_div_not_1 - - /* %ecx == 0, we are dividing by 1.0 */ - mov %edx,%eax - jmp LSecond_div_done - -LSecond_div_not_1: - divl %ecx /* Divide the numerator by the denom ms dw */ - -LSecond_div_done: - movl %eax,FPU_result_2 /* Put the result in the answer */ - - mull XsigH(%ebx) /* mul by the ms dw of the denom */ - - subl %eax,FPU_accum_1 /* Subtract from the num local reg */ - sbbl %edx,FPU_accum_2 - -#ifdef PARANOID - jc L_bugged_2 -#endif PARANOID - - movl FPU_result_2,%eax /* Get the result back */ - mull XsigL(%ebx) /* now mul the ls dw of the denom */ - - subl %eax,FPU_accum_0 /* Subtract from the num local reg */ - sbbl %edx,FPU_accum_1 /* Subtract from the num local reg */ - sbbl $0,FPU_accum_2 - -#ifdef PARANOID - jc L_bugged_2 -#endif PARANOID - - jz LDo_3rd_32_bits - -#ifdef PARANOID - cmpl $1,FPU_accum_2 - jne L_bugged_2 -#endif PARANOID - - /* need to subtract another once of the denom */ - movl XsigL(%ebx),%eax - movl XsigH(%ebx),%edx - subl %eax,FPU_accum_0 /* Subtract from the num local reg */ - sbbl %edx,FPU_accum_1 - sbbl $0,FPU_accum_2 - -#ifdef PARANOID - jc L_bugged_2 - jne L_bugged_2 -#endif PARANOID - - addl $1,FPU_result_2 /* Correct the answer */ - adcl $0,FPU_result_3 - -#ifdef PARANOID - jc L_bugged_2 /* Must check for non-zero result here */ -#endif PARANOID - -/*----------------------------------------------------------------------*/ -/* The division is essentially finished here, we just need to perform - tidying operations. - Deal with the 3rd 32 bits */ -LDo_3rd_32_bits: - /* We use an approximation for the third 32 bits. - To take account of the 3rd 32 bits of the divisor - (call them del), we subtract del * (a/b) */ - - movl FPU_result_3,%eax /* a/b */ - mull XsigLL(%ebx) /* del */ - - subl %edx,FPU_accum_1 - - /* A borrow indicates that the result is negative */ - jnb LTest_over - - movl XsigH(%ebx),%edx - addl %edx,FPU_accum_1 - - subl $1,FPU_result_2 /* Adjust the answer */ - sbbl $0,FPU_result_3 - - /* The above addition might not have been enough, check again. */ - movl FPU_accum_1,%edx /* get the reduced num */ - cmpl XsigH(%ebx),%edx /* denom */ - jb LDo_3rd_div - - movl XsigH(%ebx),%edx - addl %edx,FPU_accum_1 - - subl $1,FPU_result_2 /* Adjust the answer */ - sbbl $0,FPU_result_3 - jmp LDo_3rd_div - -LTest_over: - movl FPU_accum_1,%edx /* get the reduced num */ - - /* need to check for possible subsequent overflow */ - cmpl XsigH(%ebx),%edx /* denom */ - jb LDo_3rd_div - - /* prevent overflow */ - subl XsigH(%ebx),%edx - movl %edx,FPU_accum_1 - - addl $1,FPU_result_2 /* Reflect the subtraction in the answer */ - adcl $0,FPU_result_3 - -LDo_3rd_div: - movl FPU_accum_0,%eax - movl FPU_accum_1,%edx - divl XsigH(%ebx) - - movl %eax,FPU_result_1 /* Rough estimate of third word */ - - movl PARAM3,%esi /* pointer to answer */ - - movl FPU_result_1,%eax - movl %eax,XsigLL(%esi) - movl FPU_result_2,%eax - movl %eax,XsigL(%esi) - movl FPU_result_3,%eax - movl %eax,XsigH(%esi) - -L_exit: - popl %ebx - popl %edi - popl %esi - - leave - ret - - -#ifdef PARANOID -/* The logic is wrong if we got here */ -L_bugged: - pushl EX_INTERNAL|0x240 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_1: - pushl EX_INTERNAL|0x241 - call EXCEPTION - pop %ebx - jmp L_exit - -L_bugged_2: - pushl EX_INTERNAL|0x242 - call EXCEPTION - pop %ebx - jmp L_exit -#endif PARANOID |