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1 | #------------------------------------------------------------------------------\r |
2 | #*\r |
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3 | #* Copyright 2009 - 2010, Intel Corporation\r |
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4 | #* All rights reserved. This program and the accompanying materials\r |
5 | #* are licensed and made available under the terms and conditions of the BSD License\r |
6 | #* which accompanies this distribution. The full text of the license may be found at\r |
7 | #* http://opensource.org/licenses/bsd-license.php\r |
8 | #*\r |
9 | #* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r |
10 | #* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r |
11 | #*\r |
12 | #*\r |
13 | #------------------------------------------------------------------------------\r |
14 | \r |
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15 | #\r |
16 | # Float control word initial value: \r |
17 | # all exceptions masked, double-precision, round-to-nearest\r |
18 | #\r |
19 | ASM_PFX(mFpuControlWord): .word 0x027F\r |
20 | #\r |
21 | # Multimedia-extensions control word:\r |
22 | # all exceptions masked, round-to-nearest, flush to zero for masked underflow\r |
23 | #\r |
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24 | ASM_PFX(mMmxControlWord): .long 0x01F80\r |
25 | \r |
26 | #\r |
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27 | # Initializes floating point units for requirement of UEFI specification.\r |
28 | #\r |
29 | # This function initializes floating-point control word to 0x027F (all exceptions\r |
30 | # masked,double-precision, round-to-nearest) and multimedia-extensions control word\r |
31 | # (if supported) to 0x1F80 (all exceptions masked, round-to-nearest, flush to zero\r |
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32 | # for masked underflow).\r |
33 | #\r |
34 | ASM_GLOBAL ASM_PFX(InitializeFloatingPointUnits)\r |
35 | ASM_PFX(InitializeFloatingPointUnits):\r |
36 | \r |
37 | pushl %ebx\r |
38 | \r |
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39 | #\r |
40 | # Initialize floating point units\r |
41 | #\r |
42 | finit\r |
43 | fldcw ASM_PFX(mFpuControlWord)\r |
44 | \r |
45 | #\r |
46 | # Use CpuId instructuion (CPUID.01H:EDX.SSE[bit 25] = 1) to test\r |
47 | # whether the processor supports SSE instruction.\r |
48 | #\r |
49 | movl $1, %eax\r |
50 | cpuid\r |
51 | btl $25, %edx\r |
52 | jnc Done\r |
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53 | \r |
54 | #\r |
55 | # Set OSFXSR bit 9 in CR4\r |
56 | #\r |
57 | movl %cr4, %eax \r |
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58 | or $0x200, %eax\r |
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59 | movl %eax, %cr4\r |
60 | \r |
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61 | #\r |
62 | # The processor should support SSE instruction and we can use\r |
63 | # ldmxcsr instruction\r |
64 | #\r |
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65 | ldmxcsr ASM_PFX(mMmxControlWord)\r |
66 | \r |
67 | Done:\r |
68 | popl %ebx\r |
69 | \r |
70 | ret\r |
71 | \r |
72 | #END\r |
73 | \r |