summaryrefslogtreecommitdiff
path: root/src/lj_emit_mips.h
blob: 366cf7aba83777977f2cfaf5a86b12048ff7f7e1 (plain)
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
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
/*
** MIPS instruction emitter.
** Copyright (C) 2005-2022 Mike Pall. See Copyright Notice in luajit.h
*/

/* -- Emit basic instructions --------------------------------------------- */

static void emit_dst(ASMState *as, MIPSIns mi, Reg rd, Reg rs, Reg rt)
{
  *--as->mcp = mi | MIPSF_D(rd) | MIPSF_S(rs) | MIPSF_T(rt);
}

static void emit_dta(ASMState *as, MIPSIns mi, Reg rd, Reg rt, uint32_t a)
{
  *--as->mcp = mi | MIPSF_D(rd) | MIPSF_T(rt) | MIPSF_A(a);
}

#define emit_ds(as, mi, rd, rs)		emit_dst(as, (mi), (rd), (rs), 0)
#define emit_tg(as, mi, rt, rg)		emit_dst(as, (mi), (rg)&31, 0, (rt))

static void emit_tsi(ASMState *as, MIPSIns mi, Reg rt, Reg rs, int32_t i)
{
  *--as->mcp = mi | MIPSF_T(rt) | MIPSF_S(rs) | (i & 0xffff);
}

#define emit_ti(as, mi, rt, i)		emit_tsi(as, (mi), (rt), 0, (i))
#define emit_hsi(as, mi, rh, rs, i)	emit_tsi(as, (mi), (rh) & 31, (rs), (i))

static void emit_fgh(ASMState *as, MIPSIns mi, Reg rf, Reg rg, Reg rh)
{
  *--as->mcp = mi | MIPSF_F(rf&31) | MIPSF_G(rg&31) | MIPSF_H(rh&31);
}

#define emit_fg(as, mi, rf, rg)		emit_fgh(as, (mi), (rf), (rg), 0)

static void emit_rotr(ASMState *as, Reg dest, Reg src, Reg tmp, uint32_t shift)
{
  if ((as->flags & JIT_F_MIPS32R2)) {
    emit_dta(as, MIPSI_ROTR, dest, src, shift);
  } else {
    emit_dst(as, MIPSI_OR, dest, dest, tmp);
    emit_dta(as, MIPSI_SLL, dest, src, (-shift)&31);
    emit_dta(as, MIPSI_SRL, tmp, src, shift);
  }
}

/* -- Emit loads/stores --------------------------------------------------- */

/* Prefer rematerialization of BASE/L from global_State over spills. */
#define emit_canremat(ref)	((ref) <= REF_BASE)

/* Try to find a one step delta relative to another constant. */
static int emit_kdelta1(ASMState *as, Reg t, int32_t i)
{
  RegSet work = ~as->freeset & RSET_GPR;
  while (work) {
    Reg r = rset_picktop(work);
    IRRef ref = regcost_ref(as->cost[r]);
    lua_assert(r != t);
    if (ref < ASMREF_L) {
      int32_t delta = i - (ra_iskref(ref) ? ra_krefk(as, ref) : IR(ref)->i);
      if (checki16(delta)) {
	emit_tsi(as, MIPSI_ADDIU, t, r, delta);
	return 1;
      }
    }
    rset_clear(work, r);
  }
  return 0;  /* Failed. */
}

/* Load a 32 bit constant into a GPR. */
static void emit_loadi(ASMState *as, Reg r, int32_t i)
{
  if (checki16(i)) {
    emit_ti(as, MIPSI_LI, r, i);
  } else {
    if ((i & 0xffff)) {
      int32_t jgl = i32ptr(J2G(as->J));
      if ((uint32_t)(i-jgl) < 65536) {
	emit_tsi(as, MIPSI_ADDIU, r, RID_JGL, i-jgl-32768);
	return;
      } else if (emit_kdelta1(as, r, i)) {
	return;
      } else if ((i >> 16) == 0) {
	emit_tsi(as, MIPSI_ORI, r, RID_ZERO, i);
	return;
      }
      emit_tsi(as, MIPSI_ORI, r, r, i);
    }
    emit_ti(as, MIPSI_LUI, r, (i >> 16));
  }
}

#define emit_loada(as, r, addr)		emit_loadi(as, (r), i32ptr((addr)))

static Reg ra_allock(ASMState *as, int32_t k, RegSet allow);
static void ra_allockreg(ASMState *as, int32_t k, Reg r);

/* Get/set from constant pointer. */
static void emit_lsptr(ASMState *as, MIPSIns mi, Reg r, void *p, RegSet allow)
{
  int32_t jgl = i32ptr(J2G(as->J));
  int32_t i = i32ptr(p);
  Reg base;
  if ((uint32_t)(i-jgl) < 65536) {
    i = i-jgl-32768;
    base = RID_JGL;
  } else {
    base = ra_allock(as, i-(int16_t)i, allow);
  }
  emit_tsi(as, mi, r, base, i);
}

#define emit_loadn(as, r, tv) \
  emit_lsptr(as, MIPSI_LDC1, ((r) & 31), (void *)(tv), RSET_GPR)

/* Get/set global_State fields. */
static void emit_lsglptr(ASMState *as, MIPSIns mi, Reg r, int32_t ofs)
{
  emit_tsi(as, mi, r, RID_JGL, ofs-32768);
}

#define emit_getgl(as, r, field) \
  emit_lsglptr(as, MIPSI_LW, (r), (int32_t)offsetof(global_State, field))
#define emit_setgl(as, r, field) \
  emit_lsglptr(as, MIPSI_SW, (r), (int32_t)offsetof(global_State, field))

/* Trace number is determined from per-trace exit stubs. */
#define emit_setvmstate(as, i)		UNUSED(i)

/* -- Emit control-flow instructions -------------------------------------- */

/* Label for internal jumps. */
typedef MCode *MCLabel;

/* Return label pointing to current PC. */
#define emit_label(as)		((as)->mcp)

static void emit_branch(ASMState *as, MIPSIns mi, Reg rs, Reg rt, MCode *target)
{
  MCode *p = as->mcp;
  ptrdiff_t delta = target - p;
  lua_assert(((delta + 0x8000) >> 16) == 0);
  *--p = mi | MIPSF_S(rs) | MIPSF_T(rt) | ((uint32_t)delta & 0xffffu);
  as->mcp = p;
}

static void emit_jmp(ASMState *as, MCode *target)
{
  *--as->mcp = MIPSI_NOP;
  emit_branch(as, MIPSI_B, RID_ZERO, RID_ZERO, (target));
}

static void emit_call(ASMState *as, void *target)
{
  MCode *p = as->mcp;
  *--p = MIPSI_NOP;
  if ((((uintptr_t)target ^ (uintptr_t)p) >> 28) == 0)
    *--p = MIPSI_JAL | (((uintptr_t)target >>2) & 0x03ffffffu);
  else  /* Target out of range: need indirect call. */
    *--p = MIPSI_JALR | MIPSF_S(RID_CFUNCADDR);
  as->mcp = p;
  ra_allockreg(as, i32ptr(target), RID_CFUNCADDR);
}

/* -- Emit generic operations --------------------------------------------- */

#define emit_move(as, dst, src) \
  emit_ds(as, MIPSI_MOVE, (dst), (src))

/* Generic move between two regs. */
static void emit_movrr(ASMState *as, IRIns *ir, Reg dst, Reg src)
{
  if (dst < RID_MAX_GPR)
    emit_move(as, dst, src);
  else
    emit_fg(as, irt_isnum(ir->t) ? MIPSI_MOV_D : MIPSI_MOV_S, dst, src);
}

/* Generic load of register from stack slot. */
static void emit_spload(ASMState *as, IRIns *ir, Reg r, int32_t ofs)
{
  if (r < RID_MAX_GPR)
    emit_tsi(as, MIPSI_LW, r, RID_SP, ofs);
  else
    emit_tsi(as, irt_isnum(ir->t) ? MIPSI_LDC1 : MIPSI_LWC1,
	     (r & 31), RID_SP, ofs);
}

/* Generic store of register to stack slot. */
static void emit_spstore(ASMState *as, IRIns *ir, Reg r, int32_t ofs)
{
  if (r < RID_MAX_GPR)
    emit_tsi(as, MIPSI_SW, r, RID_SP, ofs);
  else
    emit_tsi(as, irt_isnum(ir->t) ? MIPSI_SDC1 : MIPSI_SWC1,
	     (r&31), RID_SP, ofs);
}

/* Add offset to pointer. */
static void emit_addptr(ASMState *as, Reg r, int32_t ofs)
{
  if (ofs) {
    lua_assert(checki16(ofs));
    emit_tsi(as, MIPSI_ADDIU, r, r, ofs);
  }
}

#define emit_spsub(as, ofs)	emit_addptr(as, RID_SP, -(ofs))