diff options
| author | Ralf Baechle <ralf@linux-mips.org> | 1995-11-14 08:00:00 +0000 |
|---|---|---|
| committer | <ralf@linux-mips.org> | 1995-11-14 08:00:00 +0000 |
| commit | e7c2a72e2680827d6a733931273a93461c0d8d1b (patch) | |
| tree | c9abeda78ef7504062bb2e816bcf3e3c9d680112 /arch/i386/math-emu/reg_u_mul.S | |
| parent | ec6044459060a8c9ce7f64405c465d141898548c (diff) | |
Import of Linux/MIPS 1.3.0
Diffstat (limited to 'arch/i386/math-emu/reg_u_mul.S')
| -rw-r--r-- | arch/i386/math-emu/reg_u_mul.S | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/arch/i386/math-emu/reg_u_mul.S b/arch/i386/math-emu/reg_u_mul.S new file mode 100644 index 000000000..8250666bd --- /dev/null +++ b/arch/i386/math-emu/reg_u_mul.S @@ -0,0 +1,163 @@ + .file "reg_u_mul.S" +/*---------------------------------------------------------------------------+ + | reg_u_mul.S | + | | + | Core multiplication routine | + | | + | Copyright (C) 1992,1993 | + | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | + | Australia. E-mail billm@vaxc.cc.monash.edu.au | + | | + | | + +---------------------------------------------------------------------------*/ + +/*---------------------------------------------------------------------------+ + | Basic multiplication routine. | + | Does not check the resulting exponent for overflow/underflow | + | | + | reg_u_mul(FPU_REG *a, FPU_REG *b, FPU_REG *c, unsigned int cw); | + | | + | Internal working is at approx 128 bits. | + | Result is rounded to nearest 53 or 64 bits, using "nearest or even". | + +---------------------------------------------------------------------------*/ + +#include "exception.h" +#include "fpu_asm.h" +#include "control_w.h" + + + +#ifndef NON_REENTRANT_FPU +/* Local storage on the stack: */ +#define FPU_accum_0 -4(%ebp) /* ms word */ +#define FPU_accum_1 -8(%ebp) + +#else +/* Local storage in a static area: */ +.data + .align 4,0 +FPU_accum_0: + .long 0 +FPU_accum_1: + .long 0 +#endif NON_REENTRANT_FPU + + +.text + .align 2,144 + +.globl _reg_u_mul +_reg_u_mul: + pushl %ebp + movl %esp,%ebp +#ifndef NON_REENTRANT_FPU + subl $8,%esp +#endif NON_REENTRANT_FPU + + pushl %esi + pushl %edi + pushl %ebx + + movl PARAM1,%esi + movl PARAM2,%edi + +#ifdef PARANOID + testl $0x80000000,SIGH(%esi) + jz L_bugged + testl $0x80000000,SIGH(%edi) + jz L_bugged +#endif PARANOID + +#ifdef DENORM_OPERAND + movl EXP(%esi),%eax + cmpl EXP_UNDER,%eax + jg xOp1_not_denorm + + call _denormal_operand + orl %eax,%eax + jnz fpu_Arith_exit + +xOp1_not_denorm: + movl EXP(%edi),%eax + cmpl EXP_UNDER,%eax + jg xOp2_not_denorm + + call _denormal_operand + orl %eax,%eax + jnz fpu_Arith_exit + +xOp2_not_denorm: +#endif DENORM_OPERAND + + xorl %ecx,%ecx + xorl %ebx,%ebx + + movl SIGL(%esi),%eax + mull SIGL(%edi) + movl %eax,FPU_accum_0 + movl %edx,FPU_accum_1 + + movl SIGL(%esi),%eax + mull SIGH(%edi) + addl %eax,FPU_accum_1 + adcl %edx,%ebx +/* adcl $0,%ecx // overflow here is not possible */ + + movl SIGH(%esi),%eax + mull SIGL(%edi) + addl %eax,FPU_accum_1 + adcl %edx,%ebx + adcl $0,%ecx + + movl SIGH(%esi),%eax + mull SIGH(%edi) + addl %eax,%ebx + adcl %edx,%ecx + + movl EXP(%esi),%eax /* Compute the exponent */ + addl EXP(%edi),%eax + subl EXP_BIAS-1,%eax + +/* Have now finished with the sources */ + movl PARAM3,%edi /* Point to the destination */ + movl %eax,EXP(%edi) + +/* Now make sure that the result is normalized */ + testl $0x80000000,%ecx + jnz LResult_Normalised + + /* Normalize by shifting left one bit */ + shll $1,FPU_accum_0 + rcll $1,FPU_accum_1 + rcll $1,%ebx + rcll $1,%ecx + decl EXP(%edi) + +LResult_Normalised: + movl FPU_accum_0,%eax + movl FPU_accum_1,%edx + orl %eax,%eax + jz L_extent_zero + + orl $1,%edx + +L_extent_zero: + movl %ecx,%eax + jmp fpu_reg_round + + +#ifdef PARANOID +L_bugged: + pushl EX_INTERNAL|0x205 + call EXCEPTION + pop %ebx + jmp L_exit + +L_exit: + popl %ebx + popl %edi + popl %esi + leave + ret +#endif PARANOID + |