diff options
Diffstat (limited to 'arch/i386/math-emu/reg_u_sub.S')
| -rw-r--r-- | arch/i386/math-emu/reg_u_sub.S | 272 |
1 files changed, 0 insertions, 272 deletions
diff --git a/arch/i386/math-emu/reg_u_sub.S b/arch/i386/math-emu/reg_u_sub.S deleted file mode 100644 index 1b6c24801d2..00000000000 --- a/arch/i386/math-emu/reg_u_sub.S +++ /dev/null @@ -1,272 +0,0 @@ - .file "reg_u_sub.S" -/*---------------------------------------------------------------------------+ - | reg_u_sub.S | - | | - | Core floating point subtraction routine. | - | | - | Copyright (C) 1992,1993,1995,1997 | - | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | - | E-mail billm@suburbia.net | - | | - | Call from C as: | - | int FPU_u_sub(FPU_REG *arg1, FPU_REG *arg2, FPU_REG *answ, | - | int control_w) | - | Return value is the tag of the answer, or-ed with FPU_Exception if | - | one was raised, or -1 on internal error. | - | | - +---------------------------------------------------------------------------*/ - -/* - | Kernel subtraction routine FPU_u_sub(reg *arg1, reg *arg2, reg *answ). - | Takes two valid reg f.p. numbers (TAG_Valid), which are - | treated as unsigned numbers, - | and returns their difference as a TAG_Valid or TAG_Zero f.p. - | number. - | The first number (arg1) must be the larger. - | The returned number is normalized. - | Basic checks are performed if PARANOID is defined. - */ - -#include "exception.h" -#include "fpu_emu.h" -#include "control_w.h" - -.text -ENTRY(FPU_u_sub) - pushl %ebp - movl %esp,%ebp - pushl %esi - pushl %edi - pushl %ebx - - movl PARAM1,%esi /* source 1 */ - movl PARAM2,%edi /* source 2 */ - - movl PARAM6,%ecx - subl PARAM7,%ecx /* exp1 - exp2 */ - -#ifdef PARANOID - /* source 2 is always smaller than source 1 */ - js L_bugged_1 - - testl $0x80000000,SIGH(%edi) /* The args are assumed to be be normalized */ - je L_bugged_2 - - testl $0x80000000,SIGH(%esi) - je L_bugged_2 -#endif /* PARANOID */ - -/*--------------------------------------+ - | Form a register holding the | - | smaller number | - +--------------------------------------*/ - movl SIGH(%edi),%eax /* register ms word */ - movl SIGL(%edi),%ebx /* register ls word */ - - movl PARAM3,%edi /* destination */ - movl PARAM6,%edx - movw %dx,EXP(%edi) /* Copy exponent to destination */ - - xorl %edx,%edx /* register extension */ - -/*--------------------------------------+ - | Shift the temporary register | - | right the required number of | - | places. | - +--------------------------------------*/ - - cmpw $32,%cx /* shrd only works for 0..31 bits */ - jnc L_more_than_31 - -/* less than 32 bits */ - shrd %cl,%ebx,%edx - shrd %cl,%eax,%ebx - shr %cl,%eax - jmp L_shift_done - -L_more_than_31: - cmpw $64,%cx - jnc L_more_than_63 - - subb $32,%cl - jz L_exactly_32 - - shrd %cl,%eax,%edx - shr %cl,%eax - orl %ebx,%ebx - jz L_more_31_no_low /* none of the lowest bits is set */ - - orl $1,%edx /* record the fact in the extension */ - -L_more_31_no_low: - movl %eax,%ebx - xorl %eax,%eax - jmp L_shift_done - -L_exactly_32: - movl %ebx,%edx - movl %eax,%ebx - xorl %eax,%eax - jmp L_shift_done - -L_more_than_63: - cmpw $65,%cx - jnc L_more_than_64 - - /* Shift right by 64 bits */ - movl %eax,%edx - orl %ebx,%ebx - jz L_more_63_no_low - - orl $1,%edx - jmp L_more_63_no_low - -L_more_than_64: - jne L_more_than_65 - - /* Shift right by 65 bits */ - /* Carry is clear if we get here */ - movl %eax,%edx - rcrl %edx - jnc L_shift_65_nc - - orl $1,%edx - jmp L_more_63_no_low - -L_shift_65_nc: - orl %ebx,%ebx - jz L_more_63_no_low - - orl $1,%edx - jmp L_more_63_no_low - -L_more_than_65: - movl $1,%edx /* The shifted nr always at least one '1' */ - -L_more_63_no_low: - xorl %ebx,%ebx - xorl %eax,%eax - -L_shift_done: -L_subtr: -/*------------------------------+ - | Do the subtraction | - +------------------------------*/ - xorl %ecx,%ecx - subl %edx,%ecx - movl %ecx,%edx - movl SIGL(%esi),%ecx - sbbl %ebx,%ecx - movl %ecx,%ebx - movl SIGH(%esi),%ecx - sbbl %eax,%ecx - movl %ecx,%eax - -#ifdef PARANOID - /* We can never get a borrow */ - jc L_bugged -#endif /* PARANOID */ - -/*--------------------------------------+ - | Normalize the result | - +--------------------------------------*/ - testl $0x80000000,%eax - jnz L_round /* no shifting needed */ - - orl %eax,%eax - jnz L_shift_1 /* shift left 1 - 31 bits */ - - orl %ebx,%ebx - jnz L_shift_32 /* shift left 32 - 63 bits */ - -/* - * A rare case, the only one which is non-zero if we got here - * is: 1000000 .... 0000 - * -0111111 .... 1111 1 - * -------------------- - * 0000000 .... 0000 1 - */ - - cmpl $0x80000000,%edx - jnz L_must_be_zero - - /* Shift left 64 bits */ - subw $64,EXP(%edi) - xchg %edx,%eax - jmp fpu_reg_round - -L_must_be_zero: -#ifdef PARANOID - orl %edx,%edx - jnz L_bugged_3 -#endif /* PARANOID */ - - /* The result is zero */ - movw $0,EXP(%edi) /* exponent */ - movl $0,SIGL(%edi) - movl $0,SIGH(%edi) - movl TAG_Zero,%eax - jmp L_exit - -L_shift_32: - movl %ebx,%eax - movl %edx,%ebx - movl $0,%edx - subw $32,EXP(%edi) /* Can get underflow here */ - -/* We need to shift left by 1 - 31 bits */ -L_shift_1: - bsrl %eax,%ecx /* get the required shift in %ecx */ - subl $31,%ecx - negl %ecx - shld %cl,%ebx,%eax - shld %cl,%edx,%ebx - shl %cl,%edx - subw %cx,EXP(%edi) /* Can get underflow here */ - -L_round: - jmp fpu_reg_round /* Round the result */ - - -#ifdef PARANOID -L_bugged_1: - pushl EX_INTERNAL|0x206 - call EXCEPTION - pop %ebx - jmp L_error_exit - -L_bugged_2: - pushl EX_INTERNAL|0x209 - call EXCEPTION - pop %ebx - jmp L_error_exit - -L_bugged_3: - pushl EX_INTERNAL|0x210 - call EXCEPTION - pop %ebx - jmp L_error_exit - -L_bugged_4: - pushl EX_INTERNAL|0x211 - call EXCEPTION - pop %ebx - jmp L_error_exit - -L_bugged: - pushl EX_INTERNAL|0x212 - call EXCEPTION - pop %ebx - jmp L_error_exit - -L_error_exit: - movl $-1,%eax - -#endif /* PARANOID */ - -L_exit: - popl %ebx - popl %edi - popl %esi - leave - ret |