1 /*
2 ** PPC instruction emitter.
3 ** Copyright (C) 2005-2014 Mike Pall. See Copyright Notice in luajit.h
4 */
5
6 /* -- Emit basic instructions --------------------------------------------- */
7
emit_tab(ASMState * as,PPCIns pi,Reg rt,Reg ra,Reg rb)8 static void emit_tab(ASMState *as, PPCIns pi, Reg rt, Reg ra, Reg rb)
9 {
10 *--as->mcp = pi | PPCF_T(rt) | PPCF_A(ra) | PPCF_B(rb);
11 }
12
13 #define emit_asb(as, pi, ra, rs, rb) emit_tab(as, (pi), (rs), (ra), (rb))
14 #define emit_as(as, pi, ra, rs) emit_tab(as, (pi), (rs), (ra), 0)
15 #define emit_ab(as, pi, ra, rb) emit_tab(as, (pi), 0, (ra), (rb))
16
emit_tai(ASMState * as,PPCIns pi,Reg rt,Reg ra,int32_t i)17 static void emit_tai(ASMState *as, PPCIns pi, Reg rt, Reg ra, int32_t i)
18 {
19 *--as->mcp = pi | PPCF_T(rt) | PPCF_A(ra) | (i & 0xffff);
20 }
21
22 #define emit_ti(as, pi, rt, i) emit_tai(as, (pi), (rt), 0, (i))
23 #define emit_ai(as, pi, ra, i) emit_tai(as, (pi), 0, (ra), (i))
24 #define emit_asi(as, pi, ra, rs, i) emit_tai(as, (pi), (rs), (ra), (i))
25
26 #define emit_fab(as, pi, rf, ra, rb) \
27 emit_tab(as, (pi), (rf)&31, (ra)&31, (rb)&31)
28 #define emit_fb(as, pi, rf, rb) emit_tab(as, (pi), (rf)&31, 0, (rb)&31)
29 #define emit_fac(as, pi, rf, ra, rc) \
30 emit_tab(as, (pi) | PPCF_C((rc) & 31), (rf)&31, (ra)&31, 0)
31 #define emit_facb(as, pi, rf, ra, rc, rb) \
32 emit_tab(as, (pi) | PPCF_C((rc) & 31), (rf)&31, (ra)&31, (rb)&31)
33 #define emit_fai(as, pi, rf, ra, i) emit_tai(as, (pi), (rf)&31, (ra), (i))
34
emit_rot(ASMState * as,PPCIns pi,Reg ra,Reg rs,int32_t n,int32_t b,int32_t e)35 static void emit_rot(ASMState *as, PPCIns pi, Reg ra, Reg rs,
36 int32_t n, int32_t b, int32_t e)
37 {
38 *--as->mcp = pi | PPCF_T(rs) | PPCF_A(ra) | PPCF_B(n) |
39 PPCF_MB(b) | PPCF_ME(e);
40 }
41
emit_slwi(ASMState * as,Reg ra,Reg rs,int32_t n)42 static void emit_slwi(ASMState *as, Reg ra, Reg rs, int32_t n)
43 {
44 lua_assert(n >= 0 && n < 32);
45 emit_rot(as, PPCI_RLWINM, ra, rs, n, 0, 31-n);
46 }
47
emit_rotlwi(ASMState * as,Reg ra,Reg rs,int32_t n)48 static void emit_rotlwi(ASMState *as, Reg ra, Reg rs, int32_t n)
49 {
50 lua_assert(n >= 0 && n < 32);
51 emit_rot(as, PPCI_RLWINM, ra, rs, n, 0, 31);
52 }
53
54 /* -- Emit loads/stores --------------------------------------------------- */
55
56 /* Prefer rematerialization of BASE/L from global_State over spills. */
57 #define emit_canremat(ref) ((ref) <= REF_BASE)
58
59 /* Try to find a one step delta relative to another constant. */
emit_kdelta1(ASMState * as,Reg t,int32_t i)60 static int emit_kdelta1(ASMState *as, Reg t, int32_t i)
61 {
62 RegSet work = ~as->freeset & RSET_GPR;
63 while (work) {
64 Reg r = rset_picktop(work);
65 IRRef ref = regcost_ref(as->cost[r]);
66 lua_assert(r != t);
67 if (ref < ASMREF_L) {
68 int32_t delta = i - (ra_iskref(ref) ? ra_krefk(as, ref) : IR(ref)->i);
69 if (checki16(delta)) {
70 emit_tai(as, PPCI_ADDI, t, r, delta);
71 return 1;
72 }
73 }
74 rset_clear(work, r);
75 }
76 return 0; /* Failed. */
77 }
78
79 /* Load a 32 bit constant into a GPR. */
emit_loadi(ASMState * as,Reg r,int32_t i)80 static void emit_loadi(ASMState *as, Reg r, int32_t i)
81 {
82 if (checki16(i)) {
83 emit_ti(as, PPCI_LI, r, i);
84 } else {
85 if ((i & 0xffff)) {
86 int32_t jgl = i32ptr(J2G(as->J));
87 if ((uint32_t)(i-jgl) < 65536) {
88 emit_tai(as, PPCI_ADDI, r, RID_JGL, i-jgl-32768);
89 return;
90 } else if (emit_kdelta1(as, r, i)) {
91 return;
92 }
93 emit_asi(as, PPCI_ORI, r, r, i);
94 }
95 emit_ti(as, PPCI_LIS, r, (i >> 16));
96 }
97 }
98
99 #define emit_loada(as, r, addr) emit_loadi(as, (r), i32ptr((addr)))
100
101 static Reg ra_allock(ASMState *as, int32_t k, RegSet allow);
102
103 /* Get/set from constant pointer. */
emit_lsptr(ASMState * as,PPCIns pi,Reg r,void * p,RegSet allow)104 static void emit_lsptr(ASMState *as, PPCIns pi, Reg r, void *p, RegSet allow)
105 {
106 int32_t jgl = i32ptr(J2G(as->J));
107 int32_t i = i32ptr(p);
108 Reg base;
109 if ((uint32_t)(i-jgl) < 65536) {
110 i = i-jgl-32768;
111 base = RID_JGL;
112 } else {
113 base = ra_allock(as, i-(int16_t)i, allow);
114 }
115 emit_tai(as, pi, r, base, i);
116 }
117
118 #define emit_loadn(as, r, tv) \
119 emit_lsptr(as, PPCI_LFD, ((r) & 31), (void *)(tv), RSET_GPR)
120
121 /* Get/set global_State fields. */
emit_lsglptr(ASMState * as,PPCIns pi,Reg r,int32_t ofs)122 static void emit_lsglptr(ASMState *as, PPCIns pi, Reg r, int32_t ofs)
123 {
124 emit_tai(as, pi, r, RID_JGL, ofs-32768);
125 }
126
127 #define emit_getgl(as, r, field) \
128 emit_lsglptr(as, PPCI_LWZ, (r), (int32_t)offsetof(global_State, field))
129 #define emit_setgl(as, r, field) \
130 emit_lsglptr(as, PPCI_STW, (r), (int32_t)offsetof(global_State, field))
131
132 /* Trace number is determined from per-trace exit stubs. */
133 #define emit_setvmstate(as, i) UNUSED(i)
134
135 /* -- Emit control-flow instructions -------------------------------------- */
136
137 /* Label for internal jumps. */
138 typedef MCode *MCLabel;
139
140 /* Return label pointing to current PC. */
141 #define emit_label(as) ((as)->mcp)
142
emit_condbranch(ASMState * as,PPCIns pi,PPCCC cc,MCode * target)143 static void emit_condbranch(ASMState *as, PPCIns pi, PPCCC cc, MCode *target)
144 {
145 MCode *p = --as->mcp;
146 ptrdiff_t delta = (char *)target - (char *)p;
147 lua_assert(((delta + 0x8000) >> 16) == 0);
148 pi ^= (delta & 0x8000) * (PPCF_Y/0x8000);
149 *p = pi | PPCF_CC(cc) | ((uint32_t)delta & 0xffffu);
150 }
151
emit_jmp(ASMState * as,MCode * target)152 static void emit_jmp(ASMState *as, MCode *target)
153 {
154 MCode *p = --as->mcp;
155 ptrdiff_t delta = (char *)target - (char *)p;
156 *p = PPCI_B | (delta & 0x03fffffcu);
157 }
158
emit_call(ASMState * as,void * target)159 static void emit_call(ASMState *as, void *target)
160 {
161 MCode *p = --as->mcp;
162 ptrdiff_t delta = (char *)target - (char *)p;
163 if ((((delta>>2) + 0x00800000) >> 24) == 0) {
164 *p = PPCI_BL | (delta & 0x03fffffcu);
165 } else { /* Target out of range: need indirect call. Don't use arg reg. */
166 RegSet allow = RSET_GPR & ~RSET_RANGE(RID_R0, REGARG_LASTGPR+1);
167 Reg r = ra_allock(as, i32ptr(target), allow);
168 *p = PPCI_BCTRL;
169 p[-1] = PPCI_MTCTR | PPCF_T(r);
170 as->mcp = p-1;
171 }
172 }
173
174 /* -- Emit generic operations --------------------------------------------- */
175
176 #define emit_mr(as, dst, src) \
177 emit_asb(as, PPCI_MR, (dst), (src), (src))
178
179 /* Generic move between two regs. */
emit_movrr(ASMState * as,IRIns * ir,Reg dst,Reg src)180 static void emit_movrr(ASMState *as, IRIns *ir, Reg dst, Reg src)
181 {
182 UNUSED(ir);
183 if (dst < RID_MAX_GPR)
184 emit_mr(as, dst, src);
185 else
186 emit_fb(as, PPCI_FMR, dst, src);
187 }
188
189 /* Generic load of register from stack slot. */
emit_spload(ASMState * as,IRIns * ir,Reg r,int32_t ofs)190 static void emit_spload(ASMState *as, IRIns *ir, Reg r, int32_t ofs)
191 {
192 if (r < RID_MAX_GPR)
193 emit_tai(as, PPCI_LWZ, r, RID_SP, ofs);
194 else
195 emit_fai(as, irt_isnum(ir->t) ? PPCI_LFD : PPCI_LFS, r, RID_SP, ofs);
196 }
197
198 /* Generic store of register to stack slot. */
emit_spstore(ASMState * as,IRIns * ir,Reg r,int32_t ofs)199 static void emit_spstore(ASMState *as, IRIns *ir, Reg r, int32_t ofs)
200 {
201 if (r < RID_MAX_GPR)
202 emit_tai(as, PPCI_STW, r, RID_SP, ofs);
203 else
204 emit_fai(as, irt_isnum(ir->t) ? PPCI_STFD : PPCI_STFS, r, RID_SP, ofs);
205 }
206
207 /* Emit a compare (for equality) with a constant operand. */
emit_cmpi(ASMState * as,Reg r,int32_t k)208 static void emit_cmpi(ASMState *as, Reg r, int32_t k)
209 {
210 if (checki16(k)) {
211 emit_ai(as, PPCI_CMPWI, r, k);
212 } else if (checku16(k)) {
213 emit_ai(as, PPCI_CMPLWI, r, k);
214 } else {
215 emit_ai(as, PPCI_CMPLWI, RID_TMP, k);
216 emit_asi(as, PPCI_XORIS, RID_TMP, r, (k >> 16));
217 }
218 }
219
220 /* Add offset to pointer. */
emit_addptr(ASMState * as,Reg r,int32_t ofs)221 static void emit_addptr(ASMState *as, Reg r, int32_t ofs)
222 {
223 if (ofs) {
224 emit_tai(as, PPCI_ADDI, r, r, ofs);
225 if (!checki16(ofs))
226 emit_tai(as, PPCI_ADDIS, r, r, (ofs + 32768) >> 16);
227 }
228 }
229
emit_spsub(ASMState * as,int32_t ofs)230 static void emit_spsub(ASMState *as, int32_t ofs)
231 {
232 if (ofs) {
233 emit_tai(as, PPCI_STWU, RID_TMP, RID_SP, -ofs);
234 emit_tai(as, PPCI_ADDI, RID_TMP, RID_SP,
235 CFRAME_SIZE + (as->parent ? as->parent->spadjust : 0));
236 }
237 }
238
239