diff options
Diffstat (limited to 'kernel/arch/x86/math-emu/round_Xsig.S')
| -rw-r--r-- | kernel/arch/x86/math-emu/round_Xsig.S | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/kernel/arch/x86/math-emu/round_Xsig.S b/kernel/arch/x86/math-emu/round_Xsig.S new file mode 100644 index 000000000..bbe0e8771 --- /dev/null +++ b/kernel/arch/x86/math-emu/round_Xsig.S @@ -0,0 +1,141 @@ +/*---------------------------------------------------------------------------+ + | round_Xsig.S | + | | + | Copyright (C) 1992,1993,1994,1995 | + | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | + | Australia. E-mail billm@jacobi.maths.monash.edu.au | + | | + | Normalize and round a 12 byte quantity. | + | Call from C as: | + | int round_Xsig(Xsig *n) | + | | + | Normalize a 12 byte quantity. | + | Call from C as: | + | int norm_Xsig(Xsig *n) | + | | + | Each function returns the size of the shift (nr of bits). | + | | + +---------------------------------------------------------------------------*/ + .file "round_Xsig.S" + +#include "fpu_emu.h" + + +.text +ENTRY(round_Xsig) + pushl %ebp + movl %esp,%ebp + pushl %ebx /* Reserve some space */ + pushl %ebx + pushl %esi + + movl PARAM1,%esi + + movl 8(%esi),%edx + movl 4(%esi),%ebx + movl (%esi),%eax + + movl $0,-4(%ebp) + + orl %edx,%edx /* ms bits */ + js L_round /* Already normalized */ + jnz L_shift_1 /* Shift left 1 - 31 bits */ + + movl %ebx,%edx + movl %eax,%ebx + xorl %eax,%eax + movl $-32,-4(%ebp) + +/* We need to shift left by 1 - 31 bits */ +L_shift_1: + bsrl %edx,%ecx /* get the required shift in %ecx */ + subl $31,%ecx + negl %ecx + subl %ecx,-4(%ebp) + shld %cl,%ebx,%edx + shld %cl,%eax,%ebx + shl %cl,%eax + +L_round: + testl $0x80000000,%eax + jz L_exit + + addl $1,%ebx + adcl $0,%edx + jnz L_exit + + movl $0x80000000,%edx + incl -4(%ebp) + +L_exit: + movl %edx,8(%esi) + movl %ebx,4(%esi) + movl %eax,(%esi) + + movl -4(%ebp),%eax + + popl %esi + popl %ebx + leave + ret + + + + +ENTRY(norm_Xsig) + pushl %ebp + movl %esp,%ebp + pushl %ebx /* Reserve some space */ + pushl %ebx + pushl %esi + + movl PARAM1,%esi + + movl 8(%esi),%edx + movl 4(%esi),%ebx + movl (%esi),%eax + + movl $0,-4(%ebp) + + orl %edx,%edx /* ms bits */ + js L_n_exit /* Already normalized */ + jnz L_n_shift_1 /* Shift left 1 - 31 bits */ + + movl %ebx,%edx + movl %eax,%ebx + xorl %eax,%eax + movl $-32,-4(%ebp) + + orl %edx,%edx /* ms bits */ + js L_n_exit /* Normalized now */ + jnz L_n_shift_1 /* Shift left 1 - 31 bits */ + + movl %ebx,%edx + movl %eax,%ebx + xorl %eax,%eax + addl $-32,-4(%ebp) + jmp L_n_exit /* Might not be normalized, + but shift no more. */ + +/* We need to shift left by 1 - 31 bits */ +L_n_shift_1: + bsrl %edx,%ecx /* get the required shift in %ecx */ + subl $31,%ecx + negl %ecx + subl %ecx,-4(%ebp) + shld %cl,%ebx,%edx + shld %cl,%eax,%ebx + shl %cl,%eax + +L_n_exit: + movl %edx,8(%esi) + movl %ebx,4(%esi) + movl %eax,(%esi) + + movl -4(%ebp),%eax + + popl %esi + popl %ebx + leave + ret + |