151 lines
3.2 KiB
ArmAsm
151 lines
3.2 KiB
ArmAsm
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/*---------------------------------------------------------------------------+
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| reg_norm.S |
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| Copyright (C) 1992,1993,1994 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@vaxc.cc.monash.edu.au |
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| Normalize the value in a FPU_REG. |
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| Call from C as: |
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| void normalize(FPU_REG *n) |
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| void normalize_nuo(FPU_REG *n) |
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+---------------------------------------------------------------------------*/
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#include "fpu_asm.h"
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.text
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.align 2,144
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.globl _normalize
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_normalize:
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pushl %ebp
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movl %esp,%ebp
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pushl %ebx
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movl PARAM1,%ebx
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#ifdef PARANOID
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cmpb TW_Valid,TAG(%ebx)
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je L_ok
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pushl $0x220
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call _exception
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addl $4,%esp
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L_ok:
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#endif PARANOID
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movl SIGH(%ebx),%edx
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movl SIGL(%ebx),%eax
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orl %edx,%edx /* ms bits */
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js L_done /* Already normalized */
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jnz L_shift_1 /* Shift left 1 - 31 bits */
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orl %eax,%eax
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jz L_zero /* The contents are zero */
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movl %eax,%edx
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xorl %eax,%eax
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subl $32,EXP(%ebx) /* This can cause an underflow */
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/* We need to shift left by 1 - 31 bits */
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L_shift_1:
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bsrl %edx,%ecx /* get the required shift in %ecx */
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subl $31,%ecx
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negl %ecx
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shld %cl,%eax,%edx
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shl %cl,%eax
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subl %ecx,EXP(%ebx) /* This can cause an underflow */
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movl %edx,SIGH(%ebx)
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movl %eax,SIGL(%ebx)
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L_done:
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cmpl EXP_OVER,EXP(%ebx)
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jge L_overflow
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cmpl EXP_UNDER,EXP(%ebx)
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jle L_underflow
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L_exit:
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popl %ebx
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leave
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ret
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L_zero:
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movl EXP_UNDER,EXP(%ebx)
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movb TW_Zero,TAG(%ebx)
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jmp L_exit
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L_underflow:
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push %ebx
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call _arith_underflow
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pop %ebx
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jmp L_exit
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L_overflow:
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push %ebx
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call _arith_overflow
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pop %ebx
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jmp L_exit
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/* Normalise without reporting underflow or overflow */
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.align 2,144
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.globl _normalize_nuo
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_normalize_nuo:
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pushl %ebp
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movl %esp,%ebp
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pushl %ebx
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movl PARAM1,%ebx
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#ifdef PARANOID
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cmpb TW_Valid,TAG(%ebx)
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je L_ok_nuo
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pushl $0x221
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call _exception
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addl $4,%esp
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L_ok_nuo:
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#endif PARANOID
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movl SIGH(%ebx),%edx
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movl SIGL(%ebx),%eax
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orl %edx,%edx /* ms bits */
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js L_exit /* Already normalized */
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jnz L_nuo_shift_1 /* Shift left 1 - 31 bits */
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orl %eax,%eax
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jz L_zero /* The contents are zero */
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movl %eax,%edx
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xorl %eax,%eax
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subl $32,EXP(%ebx) /* This can cause an underflow */
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/* We need to shift left by 1 - 31 bits */
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L_nuo_shift_1:
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bsrl %edx,%ecx /* get the required shift in %ecx */
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subl $31,%ecx
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negl %ecx
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shld %cl,%eax,%edx
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shl %cl,%eax
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subl %ecx,EXP(%ebx) /* This can cause an underflow */
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movl %edx,SIGH(%ebx)
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movl %eax,SIGL(%ebx)
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jmp L_exit
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