1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "runtime.h"
#pragma textflag 7
// func closure(siz int32,
// fn func(arg0, arg1, arg2 *ptr, callerpc uintptr, xxx) yyy,
// arg0, arg1, arg2 *ptr) (func(xxx) yyy)
void
·closure(int32 siz, byte *fn, byte *arg0)
{
byte *p, *q, **ret;
int32 i, n;
int32 pcrel;
if(goos != nil && strcmp((uint8*)goos, (uint8*)"nacl") == 0)
throw("no closures in native client yet");
if(siz < 0 || siz%4 != 0)
throw("bad closure size");
ret = (byte**)((byte*)&arg0 + siz);
if(siz > 100) {
// TODO(rsc): implement stack growth preamble?
throw("closure too big");
}
// compute size of new fn.
// must match code laid out below.
n = 6+5+2+1; // SUBL MOVL MOVL CLD
if(siz <= 4*4)
n += 1*siz/4; // MOVSL MOVSL...
else
n += 6+2; // MOVL REP MOVSL
n += 5; // CALL
n += 6+1; // ADDL RET
// store args aligned after code, so gc can find them.
n += siz;
if(n%4)
n += 4 - n%4;
p = mal(n);
*ret = p;
q = p + n - siz;
if(siz > 0) {
mcpy(q, (byte*)&arg0, siz);
// SUBL $siz, SP
*p++ = 0x81;
*p++ = 0xec;
*(uint32*)p = siz;
p += 4;
// MOVL $q, SI
*p++ = 0xbe;
*(byte**)p = q;
p += 4;
// MOVL SP, DI
*p++ = 0x89;
*p++ = 0xe7;
// CLD
*p++ = 0xfc;
if(siz <= 4*4) {
for(i=0; i<siz; i+=4) {
// MOVSL
*p++ = 0xa5;
}
} else {
// MOVL $(siz/4), CX [32-bit immediate siz/4]
*p++ = 0xc7;
*p++ = 0xc1;
*(uint32*)p = siz/4;
p += 4;
// REP; MOVSL
*p++ = 0xf3;
*p++ = 0xa5;
}
}
// call fn
pcrel = fn - (p+5);
// direct call with pc-relative offset
// CALL fn
*p++ = 0xe8;
*(int32*)p = pcrel;
p += 4;
// ADDL $siz, SP
*p++ = 0x81;
*p++ = 0xc4;
*(uint32*)p = siz;
p += 4;
// RET
*p++ = 0xc3;
if(p > q)
throw("bad math in sys.closure");
}
|
