bd6be579a7
Functions in math-emu are annotated as ENTRY() symbols, but their
ends are not annotated at all. But these are standard functions
called from C, with proper stack register update etc.
Omitting the ends means:
* the annotations are not paired and we cannot deal with such functions
e.g. in objtool
* the symbols are not marked as functions in the object file
* there are no sizes of the functions in the object file
So fix this by adding ENDPROC() to each such case in math-emu.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170824080624.7768-1-jslaby@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
474 lines
12 KiB
ArmAsm
474 lines
12 KiB
ArmAsm
.file "reg_u_div.S"
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/*---------------------------------------------------------------------------+
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| reg_u_div.S |
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| Divide one FPU_REG by another and put the result in a destination FPU_REG.|
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| Copyright (C) 1992,1993,1995,1997 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
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| E-mail billm@suburbia.net |
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+---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------+
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| Call from C as: |
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| int FPU_u_div(FPU_REG *a, FPU_REG *b, FPU_REG *dest, |
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| unsigned int control_word, char *sign) |
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| Does not compute the destination exponent, but does adjust it. |
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| Return value is the tag of the answer, or-ed with FPU_Exception if |
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| one was raised, or -1 on internal error. |
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+---------------------------------------------------------------------------*/
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#include "exception.h"
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#include "fpu_emu.h"
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#include "control_w.h"
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/* #define dSIGL(x) (x) */
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/* #define dSIGH(x) 4(x) */
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#ifndef NON_REENTRANT_FPU
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/*
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Local storage on the stack:
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Result: FPU_accum_3:FPU_accum_2:FPU_accum_1:FPU_accum_0
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Overflow flag: ovfl_flag
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*/
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#define FPU_accum_3 -4(%ebp)
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#define FPU_accum_2 -8(%ebp)
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#define FPU_accum_1 -12(%ebp)
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#define FPU_accum_0 -16(%ebp)
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#define FPU_result_1 -20(%ebp)
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#define FPU_result_2 -24(%ebp)
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#define FPU_ovfl_flag -28(%ebp)
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#else
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.data
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/*
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Local storage in a static area:
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Result: FPU_accum_3:FPU_accum_2:FPU_accum_1:FPU_accum_0
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Overflow flag: ovfl_flag
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*/
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.align 4,0
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FPU_accum_3:
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.long 0
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FPU_accum_2:
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.long 0
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FPU_accum_1:
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.long 0
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FPU_accum_0:
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.long 0
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FPU_result_1:
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.long 0
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FPU_result_2:
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.long 0
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FPU_ovfl_flag:
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.byte 0
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#endif /* NON_REENTRANT_FPU */
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#define REGA PARAM1
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#define REGB PARAM2
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#define DEST PARAM3
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.text
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ENTRY(FPU_u_div)
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pushl %ebp
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movl %esp,%ebp
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#ifndef NON_REENTRANT_FPU
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subl $28,%esp
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#endif /* NON_REENTRANT_FPU */
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pushl %esi
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pushl %edi
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pushl %ebx
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movl REGA,%esi
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movl REGB,%ebx
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movl DEST,%edi
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movswl EXP(%esi),%edx
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movswl EXP(%ebx),%eax
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subl %eax,%edx
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addl EXP_BIAS,%edx
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/* A denormal and a large number can cause an exponent underflow */
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cmpl EXP_WAY_UNDER,%edx
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jg xExp_not_underflow
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/* Set to a really low value allow correct handling */
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movl EXP_WAY_UNDER,%edx
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xExp_not_underflow:
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movw %dx,EXP(%edi)
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#ifdef PARANOID
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/* testl $0x80000000, SIGH(%esi) // Dividend */
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/* je L_bugged */
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testl $0x80000000, SIGH(%ebx) /* Divisor */
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je L_bugged
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#endif /* PARANOID */
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/* Check if the divisor can be treated as having just 32 bits */
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cmpl $0,SIGL(%ebx)
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jnz L_Full_Division /* Can't do a quick divide */
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/* We should be able to zip through the division here */
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movl SIGH(%ebx),%ecx /* The divisor */
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movl SIGH(%esi),%edx /* Dividend */
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movl SIGL(%esi),%eax /* Dividend */
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cmpl %ecx,%edx
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setaeb FPU_ovfl_flag /* Keep a record */
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jb L_no_adjust
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subl %ecx,%edx /* Prevent the overflow */
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L_no_adjust:
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/* Divide the 64 bit number by the 32 bit denominator */
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divl %ecx
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movl %eax,FPU_result_2
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/* Work on the remainder of the first division */
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xorl %eax,%eax
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divl %ecx
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movl %eax,FPU_result_1
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/* Work on the remainder of the 64 bit division */
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xorl %eax,%eax
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divl %ecx
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testb $255,FPU_ovfl_flag /* was the num > denom ? */
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je L_no_overflow
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/* Do the shifting here */
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/* increase the exponent */
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incw EXP(%edi)
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/* shift the mantissa right one bit */
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stc /* To set the ms bit */
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rcrl FPU_result_2
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rcrl FPU_result_1
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rcrl %eax
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L_no_overflow:
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jmp LRound_precision /* Do the rounding as required */
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/*---------------------------------------------------------------------------+
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| Divide: Return arg1/arg2 to arg3. |
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| This routine does not use the exponents of arg1 and arg2, but does |
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| adjust the exponent of arg3. |
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| The maximum returned value is (ignoring exponents) |
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| .ffffffff ffffffff |
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| ------------------ = 1.ffffffff fffffffe |
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| .80000000 00000000 |
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| and the minimum is |
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| .80000000 00000000 |
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| ------------------ = .80000000 00000001 (rounded) |
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| .ffffffff ffffffff |
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+---------------------------------------------------------------------------*/
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L_Full_Division:
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/* Save extended dividend in local register */
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movl SIGL(%esi),%eax
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movl %eax,FPU_accum_2
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movl SIGH(%esi),%eax
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movl %eax,FPU_accum_3
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xorl %eax,%eax
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movl %eax,FPU_accum_1 /* zero the extension */
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movl %eax,FPU_accum_0 /* zero the extension */
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movl SIGL(%esi),%eax /* Get the current num */
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movl SIGH(%esi),%edx
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/*----------------------------------------------------------------------*/
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/* Initialization done.
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Do the first 32 bits. */
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movb $0,FPU_ovfl_flag
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cmpl SIGH(%ebx),%edx /* Test for imminent overflow */
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jb LLess_than_1
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ja LGreater_than_1
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cmpl SIGL(%ebx),%eax
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jb LLess_than_1
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LGreater_than_1:
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/* The dividend is greater or equal, would cause overflow */
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setaeb FPU_ovfl_flag /* Keep a record */
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subl SIGL(%ebx),%eax
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sbbl SIGH(%ebx),%edx /* Prevent the overflow */
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movl %eax,FPU_accum_2
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movl %edx,FPU_accum_3
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LLess_than_1:
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/* At this point, we have a dividend < divisor, with a record of
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adjustment in FPU_ovfl_flag */
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/* We will divide by a number which is too large */
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movl SIGH(%ebx),%ecx
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addl $1,%ecx
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jnc LFirst_div_not_1
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/* here we need to divide by 100000000h,
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i.e., no division at all.. */
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mov %edx,%eax
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jmp LFirst_div_done
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LFirst_div_not_1:
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divl %ecx /* Divide the numerator by the augmented
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denom ms dw */
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LFirst_div_done:
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movl %eax,FPU_result_2 /* Put the result in the answer */
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mull SIGH(%ebx) /* mul by the ms dw of the denom */
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subl %eax,FPU_accum_2 /* Subtract from the num local reg */
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sbbl %edx,FPU_accum_3
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movl FPU_result_2,%eax /* Get the result back */
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mull SIGL(%ebx) /* now mul the ls dw of the denom */
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subl %eax,FPU_accum_1 /* Subtract from the num local reg */
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sbbl %edx,FPU_accum_2
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sbbl $0,FPU_accum_3
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je LDo_2nd_32_bits /* Must check for non-zero result here */
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#ifdef PARANOID
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jb L_bugged_1
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#endif /* PARANOID */
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/* need to subtract another once of the denom */
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incl FPU_result_2 /* Correct the answer */
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movl SIGL(%ebx),%eax
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movl SIGH(%ebx),%edx
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subl %eax,FPU_accum_1 /* Subtract from the num local reg */
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sbbl %edx,FPU_accum_2
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#ifdef PARANOID
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sbbl $0,FPU_accum_3
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jne L_bugged_1 /* Must check for non-zero result here */
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#endif /* PARANOID */
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/*----------------------------------------------------------------------*/
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/* Half of the main problem is done, there is just a reduced numerator
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to handle now.
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Work with the second 32 bits, FPU_accum_0 not used from now on */
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LDo_2nd_32_bits:
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movl FPU_accum_2,%edx /* get the reduced num */
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movl FPU_accum_1,%eax
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/* need to check for possible subsequent overflow */
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cmpl SIGH(%ebx),%edx
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jb LDo_2nd_div
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ja LPrevent_2nd_overflow
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cmpl SIGL(%ebx),%eax
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jb LDo_2nd_div
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LPrevent_2nd_overflow:
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/* The numerator is greater or equal, would cause overflow */
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/* prevent overflow */
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subl SIGL(%ebx),%eax
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sbbl SIGH(%ebx),%edx
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movl %edx,FPU_accum_2
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movl %eax,FPU_accum_1
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incl FPU_result_2 /* Reflect the subtraction in the answer */
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#ifdef PARANOID
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je L_bugged_2 /* Can't bump the result to 1.0 */
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#endif /* PARANOID */
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LDo_2nd_div:
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cmpl $0,%ecx /* augmented denom msw */
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jnz LSecond_div_not_1
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/* %ecx == 0, we are dividing by 1.0 */
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mov %edx,%eax
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jmp LSecond_div_done
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LSecond_div_not_1:
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divl %ecx /* Divide the numerator by the denom ms dw */
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LSecond_div_done:
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movl %eax,FPU_result_1 /* Put the result in the answer */
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mull SIGH(%ebx) /* mul by the ms dw of the denom */
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subl %eax,FPU_accum_1 /* Subtract from the num local reg */
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sbbl %edx,FPU_accum_2
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#ifdef PARANOID
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jc L_bugged_2
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#endif /* PARANOID */
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movl FPU_result_1,%eax /* Get the result back */
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mull SIGL(%ebx) /* now mul the ls dw of the denom */
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subl %eax,FPU_accum_0 /* Subtract from the num local reg */
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sbbl %edx,FPU_accum_1 /* Subtract from the num local reg */
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sbbl $0,FPU_accum_2
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#ifdef PARANOID
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jc L_bugged_2
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#endif /* PARANOID */
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jz LDo_3rd_32_bits
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#ifdef PARANOID
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cmpl $1,FPU_accum_2
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jne L_bugged_2
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#endif /* PARANOID */
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/* need to subtract another once of the denom */
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movl SIGL(%ebx),%eax
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movl SIGH(%ebx),%edx
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subl %eax,FPU_accum_0 /* Subtract from the num local reg */
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sbbl %edx,FPU_accum_1
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sbbl $0,FPU_accum_2
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#ifdef PARANOID
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jc L_bugged_2
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jne L_bugged_2
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#endif /* PARANOID */
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addl $1,FPU_result_1 /* Correct the answer */
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adcl $0,FPU_result_2
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#ifdef PARANOID
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jc L_bugged_2 /* Must check for non-zero result here */
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#endif /* PARANOID */
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/*----------------------------------------------------------------------*/
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/* The division is essentially finished here, we just need to perform
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tidying operations.
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Deal with the 3rd 32 bits */
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LDo_3rd_32_bits:
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movl FPU_accum_1,%edx /* get the reduced num */
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movl FPU_accum_0,%eax
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/* need to check for possible subsequent overflow */
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cmpl SIGH(%ebx),%edx /* denom */
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jb LRound_prep
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ja LPrevent_3rd_overflow
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cmpl SIGL(%ebx),%eax /* denom */
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jb LRound_prep
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LPrevent_3rd_overflow:
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/* prevent overflow */
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subl SIGL(%ebx),%eax
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sbbl SIGH(%ebx),%edx
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movl %edx,FPU_accum_1
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movl %eax,FPU_accum_0
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addl $1,FPU_result_1 /* Reflect the subtraction in the answer */
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adcl $0,FPU_result_2
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jne LRound_prep
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jnc LRound_prep
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/* This is a tricky spot, there is an overflow of the answer */
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movb $255,FPU_ovfl_flag /* Overflow -> 1.000 */
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LRound_prep:
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/*
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* Prepare for rounding.
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* To test for rounding, we just need to compare 2*accum with the
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* denom.
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*/
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movl FPU_accum_0,%ecx
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movl FPU_accum_1,%edx
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movl %ecx,%eax
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orl %edx,%eax
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jz LRound_ovfl /* The accumulator contains zero. */
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/* Multiply by 2 */
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clc
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rcll $1,%ecx
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rcll $1,%edx
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jc LRound_large /* No need to compare, denom smaller */
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subl SIGL(%ebx),%ecx
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sbbl SIGH(%ebx),%edx
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jnc LRound_not_small
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movl $0x70000000,%eax /* Denom was larger */
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jmp LRound_ovfl
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LRound_not_small:
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jnz LRound_large
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movl $0x80000000,%eax /* Remainder was exactly 1/2 denom */
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jmp LRound_ovfl
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LRound_large:
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movl $0xff000000,%eax /* Denom was smaller */
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LRound_ovfl:
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/* We are now ready to deal with rounding, but first we must get
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the bits properly aligned */
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testb $255,FPU_ovfl_flag /* was the num > denom ? */
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je LRound_precision
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incw EXP(%edi)
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/* shift the mantissa right one bit */
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stc /* Will set the ms bit */
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rcrl FPU_result_2
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rcrl FPU_result_1
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rcrl %eax
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/* Round the result as required */
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LRound_precision:
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decw EXP(%edi) /* binary point between 1st & 2nd bits */
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movl %eax,%edx
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movl FPU_result_1,%ebx
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movl FPU_result_2,%eax
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jmp fpu_reg_round
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#ifdef PARANOID
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/* The logic is wrong if we got here */
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L_bugged:
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pushl EX_INTERNAL|0x202
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call EXCEPTION
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pop %ebx
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jmp L_exit
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L_bugged_1:
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pushl EX_INTERNAL|0x203
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call EXCEPTION
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pop %ebx
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jmp L_exit
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L_bugged_2:
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pushl EX_INTERNAL|0x204
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call EXCEPTION
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pop %ebx
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jmp L_exit
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L_exit:
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movl $-1,%eax
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popl %ebx
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popl %edi
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popl %esi
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leave
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ret
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#endif /* PARANOID */
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ENDPROC(FPU_u_div)
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