75 lines
1.5 KiB
NASM
75 lines
1.5 KiB
NASM
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; Sys_SnapVector NASM code (Andrew Henderson)
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; See win32/win_shared.c for the Win32 equivalent
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; This code is provided to ensure that the
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; rounding behavior (and, if necessary, the
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; precision) of DLL and QVM code are identical
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; e.g. for network-visible operations.
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; See ftol.nasm for operations on a single float,
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; as used in compiled VM and DLL code that does
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; not use this system trap.
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;
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segment .data
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fpucw dd 0
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cw037F dd 0x037F ; Rounding to nearest (even).
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segment .text
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; void Sys_SnapVector( float *v )
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global Sys_SnapVector
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Sys_SnapVector:
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push eax
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push ebp
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mov ebp, esp
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fnstcw [fpucw]
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mov eax, dword [ebp + 12]
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fldcw [cw037F]
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fld dword [eax]
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fistp dword [eax]
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fild dword [eax]
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fstp dword [eax]
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fld dword [eax + 4]
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fistp dword [eax + 4]
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fild dword [eax + 4]
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fstp dword [eax + 4]
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fld dword [eax + 8]
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fistp dword [eax + 8]
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fild dword [eax + 8]
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fstp dword [eax + 8]
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fldcw [fpucw]
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pop ebp
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pop eax
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ret
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; void Sys_SnapVectorCW( float *v, unsigned short int cw )
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global Sys_SnapVectorCW
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Sys_SnapVector_cw:
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push eax
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push ebp
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mov ebp, esp
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fnstcw [fpucw]
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mov eax, dword [ebp + 12]
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fldcw [ebp + 16]
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fld dword [eax]
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fistp dword [eax]
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fild dword [eax]
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fstp dword [eax]
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fld dword [eax + 4]
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fistp dword [eax + 4]
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fild dword [eax + 4]
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fstp dword [eax + 4]
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fld dword [eax + 8]
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fistp dword [eax + 8]
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fild dword [eax + 8]
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fstp dword [eax + 8]
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fldcw [fpucw]
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pop ebp
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pop eax
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ret
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