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7b414b4e | 1 | ;/** @file\r |
f45af90b | 2 | ; \r |
3 | ; This code provides low level routines that support the Virtual Machine\r | |
4 | ; for option ROMs.\r | |
5 | ; \r | |
7b414b4e | 6 | ; Copyright (c) 2006 - 2008, Intel Corporation. <BR>\r |
7 | ; All rights reserved. This program and the accompanying materials\r | |
8 | ; are licensed and made available under the terms and conditions of the BSD License\r | |
9 | ; which accompanies this distribution. The full text of the license may be found at\r | |
10 | ; http://opensource.org/licenses/bsd-license.php\r | |
f45af90b | 11 | ; \r |
7b414b4e | 12 | ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r |
13 | ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
f45af90b | 14 | ; \r |
7b414b4e | 15 | ;**/\r |
16 | \r | |
17 | page ,132\r | |
18 | title VM ASSEMBLY LANGUAGE ROUTINES\r | |
53c71d09 | 19 | \r |
20 | ;---------------------------------------------------------------------------\r | |
21 | ; Equate files needed.\r | |
22 | ;---------------------------------------------------------------------------\r | |
23 | \r | |
24 | .XLIST\r | |
25 | \r | |
26 | .LIST\r | |
27 | \r | |
28 | ;---------------------------------------------------------------------------\r | |
29 | ; Assembler options\r | |
30 | ;---------------------------------------------------------------------------\r | |
31 | \r | |
32 | .686p\r | |
7b414b4e | 33 | .model flat\r |
34 | .code\r | |
53c71d09 | 35 | ;---------------------------------------------------------------------------\r |
36 | ;;GenericPostSegment SEGMENT USE16\r | |
37 | ;---------------------------------------------------------------------------\r | |
38 | CopyMem PROTO C Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD\r | |
39 | \r | |
40 | ;****************************************************************************\r | |
41 | ; EbcLLCALLEXNative\r | |
42 | ;\r | |
43 | ; This function is called to execute an EBC CALLEX instruction\r | |
7b414b4e | 44 | ; to native code.\r |
53c71d09 | 45 | ; This instruction requires that we thunk out to external native\r |
7b414b4e | 46 | ; code. For IA32, we simply switch stacks and jump to the\r |
53c71d09 | 47 | ; specified function. On return, we restore the stack pointer\r |
48 | ; to its original location.\r | |
49 | ;\r | |
50 | ; Destroys no working registers.\r | |
51 | ;****************************************************************************\r | |
52 | ; VOID EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)\r | |
53 | _EbcLLCALLEXNative PROC NEAR PUBLIC\r | |
54 | push ebp\r | |
55 | push ebx\r | |
56 | mov ebp, esp ; standard function prolog\r | |
7b414b4e | 57 | \r |
53c71d09 | 58 | ; Get function address in a register\r |
59 | ; mov ecx, FuncAddr => mov ecx, dword ptr [FuncAddr]\r | |
60 | mov ecx, dword ptr [esp]+0Ch\r | |
7b414b4e | 61 | \r |
53c71d09 | 62 | ; Set stack pointer to new value\r |
63 | ; mov eax, NewStackPointer => mov eax, dword ptr [NewSp]\r | |
64 | mov eax, dword ptr [esp] + 14h\r | |
65 | mov edx, dword ptr [esp] + 10h\r | |
66 | sub eax, edx\r | |
7b414b4e | 67 | sub esp, eax\r |
53c71d09 | 68 | mov ebx, esp\r |
69 | push ecx\r | |
70 | push eax\r | |
71 | push edx\r | |
72 | push ebx\r | |
73 | call CopyMem\r | |
74 | pop eax\r | |
75 | pop eax\r | |
76 | pop eax\r | |
77 | pop ecx\r | |
78 | \r | |
79 | ; Now call the external routine\r | |
80 | call ecx\r | |
7b414b4e | 81 | \r |
53c71d09 | 82 | ; ebp is preserved by the callee. In this function it\r |
83 | ; equals the original esp, so set them equal\r | |
84 | mov esp, ebp\r | |
85 | \r | |
86 | ; Standard function epilog\r | |
87 | mov esp, ebp\r | |
88 | pop ebx\r | |
89 | pop ebp\r | |
90 | ret\r | |
91 | _EbcLLCALLEXNative ENDP\r | |
92 | \r | |
93 | \r | |
94 | ; UINTN EbcLLGetEbcEntryPoint(VOID);\r | |
95 | ; Routine Description:\r | |
96 | ; The VM thunk code stuffs an EBC entry point into a processor\r | |
97 | ; register. Since we can't use inline assembly to get it from\r | |
7b414b4e | 98 | ; the interpreter C code, stuff it into the return value\r |
53c71d09 | 99 | ; register and return.\r |
100 | ;\r | |
101 | ; Arguments:\r | |
102 | ; None.\r | |
103 | ;\r | |
104 | ; Returns:\r | |
105 | ; The contents of the register in which the entry point is passed.\r | |
106 | ;\r | |
107 | _EbcLLGetEbcEntryPoint PROC NEAR PUBLIC\r | |
108 | ret\r | |
109 | _EbcLLGetEbcEntryPoint ENDP\r | |
110 | \r | |
111 | ;/*++\r | |
112 | ;\r | |
113 | ;Routine Description:\r | |
7b414b4e | 114 | ;\r |
53c71d09 | 115 | ; Return the caller's value of the stack pointer.\r |
116 | ;\r | |
117 | ;Arguments:\r | |
118 | ;\r | |
119 | ; None.\r | |
120 | ;\r | |
121 | ;Returns:\r | |
122 | ;\r | |
123 | ; The current value of the stack pointer for the caller. We\r | |
124 | ; adjust it by 4 here because when they called us, the return address\r | |
125 | ; is put on the stack, thereby lowering it by 4 bytes.\r | |
126 | ;\r | |
127 | ;--*/\r | |
128 | \r | |
7b414b4e | 129 | ; UINTN EbcLLGetStackPointer()\r |
53c71d09 | 130 | _EbcLLGetStackPointer PROC NEAR PUBLIC\r |
131 | mov eax, esp ; get current stack pointer\r | |
132 | add eax, 4 ; stack adjusted by this much when we were called\r | |
133 | ret\r | |
134 | _EbcLLGetStackPointer ENDP\r | |
135 | \r | |
136 | ; UINT64 EbcLLGetReturnValue(VOID);\r | |
137 | ; Routine Description:\r | |
138 | ; When EBC calls native, on return the VM has to stuff the return\r | |
139 | ; value into a VM register. It's assumed here that the value is still\r | |
140 | ; in the register, so simply return and the caller should get the\r | |
141 | ; return result properly.\r | |
142 | ;\r | |
143 | ; Arguments:\r | |
144 | ; None.\r | |
145 | ;\r | |
146 | ; Returns:\r | |
147 | ; The unmodified value returned by the native code.\r | |
148 | ;\r | |
149 | _EbcLLGetReturnValue PROC NEAR PUBLIC\r | |
150 | ret\r | |
151 | _EbcLLGetReturnValue ENDP\r | |
152 | \r | |
153 | END\r |