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| /* SPDX-License-Identifier: GPL-2.0 */
| /*---------------------------------------------------------------------------+
| | reg_norm.S |
| | |
| | Copyright (C) 1992,1993,1994,1995,1997 |
| | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
| | Australia. E-mail billm@suburbia.net |
| | |
| | Normalize the value in a FPU_REG. |
| | |
| | Call from C as: |
| | int FPU_normalize(FPU_REG *n) |
| | |
| | int FPU_normalize_nuo(FPU_REG *n) |
| | |
| | Return value is the tag of the answer, or-ed with FPU_Exception if |
| | one was raised, or -1 on internal error. |
| | |
| +---------------------------------------------------------------------------*/
|
| #include "fpu_emu.h"
|
|
| .text
| ENTRY(FPU_normalize)
| pushl %ebp
| movl %esp,%ebp
| pushl %ebx
|
| movl PARAM1,%ebx
|
| movl SIGH(%ebx),%edx
| movl SIGL(%ebx),%eax
|
| orl %edx,%edx /* ms bits */
| js L_done /* Already normalized */
| jnz L_shift_1 /* Shift left 1 - 31 bits */
|
| orl %eax,%eax
| jz L_zero /* The contents are zero */
|
| movl %eax,%edx
| xorl %eax,%eax
| subw $32,EXP(%ebx) /* This can cause an underflow */
|
| /* 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
| shld %cl,%eax,%edx
| shl %cl,%eax
| subw %cx,EXP(%ebx) /* This can cause an underflow */
|
| movl %edx,SIGH(%ebx)
| movl %eax,SIGL(%ebx)
|
| L_done:
| cmpw EXP_OVER,EXP(%ebx)
| jge L_overflow
|
| cmpw EXP_UNDER,EXP(%ebx)
| jle L_underflow
|
| L_exit_valid:
| movl TAG_Valid,%eax
|
| /* Convert the exponent to 80x87 form. */
| addw EXTENDED_Ebias,EXP(%ebx)
| andw $0x7fff,EXP(%ebx)
|
| L_exit:
| popl %ebx
| leave
| ret
|
|
| L_zero:
| movw $0,EXP(%ebx)
| movl TAG_Zero,%eax
| jmp L_exit
|
| L_underflow:
| /* Convert the exponent to 80x87 form. */
| addw EXTENDED_Ebias,EXP(%ebx)
| push %ebx
| call arith_underflow
| pop %ebx
| jmp L_exit
|
| L_overflow:
| /* Convert the exponent to 80x87 form. */
| addw EXTENDED_Ebias,EXP(%ebx)
| push %ebx
| call arith_overflow
| pop %ebx
| jmp L_exit
| ENDPROC(FPU_normalize)
|
|
|
| /* Normalise without reporting underflow or overflow */
| ENTRY(FPU_normalize_nuo)
| pushl %ebp
| movl %esp,%ebp
| pushl %ebx
|
| movl PARAM1,%ebx
|
| movl SIGH(%ebx),%edx
| movl SIGL(%ebx),%eax
|
| orl %edx,%edx /* ms bits */
| js L_exit_nuo_valid /* Already normalized */
| jnz L_nuo_shift_1 /* Shift left 1 - 31 bits */
|
| orl %eax,%eax
| jz L_exit_nuo_zero /* The contents are zero */
|
| movl %eax,%edx
| xorl %eax,%eax
| subw $32,EXP(%ebx) /* This can cause an underflow */
|
| /* We need to shift left by 1 - 31 bits */
| L_nuo_shift_1:
| bsrl %edx,%ecx /* get the required shift in %ecx */
| subl $31,%ecx
| negl %ecx
| shld %cl,%eax,%edx
| shl %cl,%eax
| subw %cx,EXP(%ebx) /* This can cause an underflow */
|
| movl %edx,SIGH(%ebx)
| movl %eax,SIGL(%ebx)
|
| L_exit_nuo_valid:
| movl TAG_Valid,%eax
|
| popl %ebx
| leave
| ret
|
| L_exit_nuo_zero:
| movl TAG_Zero,%eax
| movw EXP_UNDER,EXP(%ebx)
|
| popl %ebx
| leave
| ret
| ENDPROC(FPU_normalize_nuo)
|
|
