riscv64-asm.c

   1 /*************************************************************/
   2 /*
   3  *  RISCV64 assembler for TCC
   4  *
   5  */
   6
   7 #ifdef TARGET_DEFS_ONLY
   8
   9 #define CONFIG_TCC_ASM
  10 #define NB_ASM_REGS 32
  11
  12 ST_FUNC void g(int c);
  13 ST_FUNC void gen_le16(int c);
  14 ST_FUNC void gen_le32(int c);
  15
  16 /*************************************************************/
  17 #else
  18 /*************************************************************/
  19 #define USING_GLOBALS
  20 #include "tcc.h"
  21
  22 /* XXX: make it faster ? */
  23 ST_FUNC void g(int c)
  24 {
  25     int ind1;
  26     if (nocode_wanted)
  27         return;
  28     ind1 = ind + 1;
  29     if (ind1 > cur_text_section->data_allocated)
  30         section_realloc(cur_text_section, ind1);
  31     cur_text_section->data[ind] = c;
  32     ind = ind1;
  33 }
  34
  35 ST_FUNC void gen_le16 (int i)
  36 {
  37     g(i);
  38     g(i>>8);
  39 }
  40
  41 ST_FUNC void gen_le32 (int i)
  42 {
  43     int ind1;
  44     if (nocode_wanted)
  45         return;
  46     ind1 = ind + 4;
  47     if (ind1 > cur_text_section->data_allocated)
  48         section_realloc(cur_text_section, ind1);
  49     cur_text_section->data[ind++] = i & 0xFF;
  50     cur_text_section->data[ind++] = (i >> 8) & 0xFF;
  51     cur_text_section->data[ind++] = (i >> 16) & 0xFF;
  52     cur_text_section->data[ind++] = (i >> 24) & 0xFF;
  53 }
  54
  55 ST_FUNC void gen_expr32(ExprValue *pe)
  56 {
  57     gen_le32(pe->v);
  58 }
  59
  60 static void asm_emit_opcode(uint32_t opcode) {
  61     gen_le32(opcode);
  62 }
  63
  64 static void asm_nullary_opcode(TCCState *s1, int token)
  65 {
  66     switch (token) {
  67     // Sync instructions
  68
  69     case TOK_ASM_fence: // I
  70         asm_emit_opcode((0x3 << 2) | 3 | (0 << 12));
  71         return;
  72     case TOK_ASM_fence_i: // I
  73         asm_emit_opcode((0x3 << 2) | 3| (1 << 12));
  74         return;
  75
  76     // System calls
  77
  78     case TOK_ASM_scall: // I (pseudo)
  79         asm_emit_opcode((0x1C << 2) | 3 | (0 << 12));
  80         return;
  81     case TOK_ASM_sbreak: // I (pseudo)
  82         asm_emit_opcode((0x1C << 2) | 3 | (0 << 12) | (1 << 20));
  83         return;
  84
  85     // Privileged Instructions
  86
  87     case TOK_ASM_ecall:
  88         asm_emit_opcode((0x1C << 2) | 3 | (0 << 20));
  89         return;
  90     case TOK_ASM_ebreak:
  91         asm_emit_opcode((0x1C << 2) | 3 | (1 << 20));
  92         return;
  93
  94     // Other
  95
  96     case TOK_ASM_wfi:
  97         asm_emit_opcode((0x1C << 2) | 3 | (0x105 << 20));
  98         return;
  99
 100     default:
 101         expect("nullary instruction");
 102     }
 103 }
 104
 105 enum {
 106     OPT_REG,
 107     OPT_IM12S,
 108     OPT_IM32,
 109 };
 110 #define OP_REG    (1 << OPT_REG)
 111 #define OP_IM32   (1 << OPT_IM32)
 112 #define OP_IM12S   (1 << OPT_IM12S)
 113
 114 typedef struct Operand {
 115     uint32_t type;
 116     union {
 117         uint8_t reg;
 118         uint16_t regset;
 119         ExprValue e;
 120     };
 121 } Operand;
 122
 123 /* Parse a text containing operand and store the result in OP */
 124 static void parse_operand(TCCState *s1, Operand *op)
 125 {
 126     ExprValue e;
 127     int8_t reg;
 128
 129     op->type = 0;
 130
 131     if ((reg = asm_parse_regvar(tok)) != -1) {
 132         next(); // skip register name
 133         op->type = OP_REG;
 134         op->reg = (uint8_t) reg;
 135         return;
 136     } else if (tok == '$') {
 137         /* constant value */
 138         next(); // skip '#' or '$'
 139     }
 140     asm_expr(s1, &e);
 141     op->type = OP_IM32;
 142     op->e = e;
 143     if (!op->e.sym) {
 144         if ((int) op->e.v >= -2048 && (int) op->e.v < 2048)
 145             op->type = OP_IM12S;
 146     } else
 147         expect("operand");
 148 }
 149
 150 #define ENCODE_RS1(register_index) ((register_index) << 15)
 151 #define ENCODE_RS2(register_index) ((register_index) << 20)
 152 #define ENCODE_RD(register_index) ((register_index) << 7)
 153
 154 // Note: Those all map to CSR--so they are pseudo-instructions.
 155 static void asm_unary_opcode(TCCState *s1, int token)
 156 {
 157     uint32_t opcode = (0x1C << 2) | 3 | (2 << 12);
 158     Operand op;
 159     parse_operand(s1, &op);
 160     if (op.type != OP_REG) {
 161         expect("register");
 162         return;
 163     }
 164     opcode |= ENCODE_RD(op.reg);
 165
 166     switch (token) {
 167     case TOK_ASM_rdcycle:
 168         asm_emit_opcode(opcode | (0xC00 << 20));
 169         return;
 170     case TOK_ASM_rdcycleh:
 171         asm_emit_opcode(opcode | (0xC80 << 20));
 172         return;
 173     case TOK_ASM_rdtime:
 174         asm_emit_opcode(opcode | (0xC01 << 20) | ENCODE_RD(op.reg));
 175         return;
 176     case TOK_ASM_rdtimeh:
 177         asm_emit_opcode(opcode | (0xC81 << 20) | ENCODE_RD(op.reg));
 178         return;
 179     case TOK_ASM_rdinstret:
 180         asm_emit_opcode(opcode | (0xC02 << 20) | ENCODE_RD(op.reg));
 181         return;
 182     case TOK_ASM_rdinstreth:
 183         asm_emit_opcode(opcode | (0xC82 << 20) | ENCODE_RD(op.reg));
 184         return;
 185     default:
 186         expect("unary instruction");
 187     }
 188 }
 189
 190 static void asm_emit_u(int token, uint32_t opcode, const Operand* rd, const Operand* rs2)
 191 {
 192     if (rd->type != OP_REG) {
 193         tcc_error("'%s': Expected destination operand that is a register", get_tok_str(token, NULL));
 194         return;
 195     }
 196     if (rs2->type != OP_IM12S && rs2->type != OP_IM32) {
 197         tcc_error("'%s': Expected second source operand that is an immediate value", get_tok_str(token, NULL));
 198         return;
 199     } else if (rs2->e.v >= 0x100000) {
 200         tcc_error("'%s': Expected second source operand that is an immediate value between 0 and 0xfffff", get_tok_str(token, NULL));
 201         return;
 202     }
 203     /* U-type instruction:
 204               31...12 imm[31:12]
 205               11...7 rd
 206               6...0 opcode */
 207     gen_le32(opcode | ENCODE_RD(rd->reg) | (rs2->e.v << 12));
 208 }
 209
 210 static void asm_binary_opcode(TCCState* s1, int token)
 211 {
 212     Operand ops[2];
 213     parse_operand(s1, &ops[0]);
 214     if (tok == ',')
 215         next();
 216     else
 217         expect("','");
 218     parse_operand(s1, &ops[1]);
 219
 220     switch (token) {
 221     case TOK_ASM_lui:
 222         asm_emit_u(token, (0xD << 2) | 3, &ops[0], &ops[1]);
 223         return;
 224     case TOK_ASM_auipc:
 225         asm_emit_u(token, (0x05 << 2) | 3, &ops[0], &ops[1]);
 226         return;
 227     default:
 228         expect("binary instruction");
 229     }
 230 }
 231
 232 /* caller: Add funct3, funct7 into opcode */
 233 static void asm_emit_r(int token, uint32_t opcode, const Operand* rd, const Operand* rs1, const Operand* rs2)
 234 {
 235     if (rd->type != OP_REG) {
 236         tcc_error("'%s': Expected destination operand that is a register", get_tok_str(token, NULL));
 237         return;
 238     }
 239     if (rs1->type != OP_REG) {
 240         tcc_error("'%s': Expected first source operand that is a register", get_tok_str(token, NULL));
 241         return;
 242     }
 243     if (rs2->type != OP_REG) {
 244         tcc_error("'%s': Expected second source operand that is a register or immediate", get_tok_str(token, NULL));
 245         return;
 246     }
 247     /* R-type instruction:
 248              31...25 funct7
 249              24...20 rs2
 250              19...15 rs1
 251              14...12 funct3
 252              11...7 rd
 253              6...0 opcode */
 254     gen_le32(opcode | ENCODE_RD(rd->reg) | ENCODE_RS1(rs1->reg) | ENCODE_RS2(rs2->reg));
 255 }
 256
 257 /* caller: Add funct3 into opcode */
 258 static void asm_emit_i(int token, uint32_t opcode, const Operand* rd, const Operand* rs1, const Operand* rs2)
 259 {
 260     if (rd->type != OP_REG) {
 261         tcc_error("'%s': Expected destination operand that is a register", get_tok_str(token, NULL));
 262         return;
 263     }
 264     if (rs1->type != OP_REG) {
 265         tcc_error("'%s': Expected first source operand that is a register", get_tok_str(token, NULL));
 266         return;
 267     }
 268     if (rs2->type != OP_IM12S) {
 269         tcc_error("'%s': Expected second source operand that is an immediate value between 0 and 4095", get_tok_str(token, NULL));
 270         return;
 271     }
 272     /* I-type instruction:
 273              31...20 imm[11:0]
 274              19...15 rs1
 275              14...12 funct3
 276              11...7 rd
 277              6...0 opcode */
 278
 279     gen_le32(opcode | ENCODE_RD(rd->reg) | ENCODE_RS1(rs1->reg) | (rs2->e.v << 20));
 280 }
 281
 282 static void asm_shift_opcode(TCCState *s1, int token)
 283 {
 284     Operand ops[3];
 285     parse_operand(s1, &ops[0]);
 286     if (tok == ',')
 287         next();
 288     else
 289         expect("','");
 290     parse_operand(s1, &ops[1]);
 291     if (tok == ',')
 292         next();
 293     else
 294         expect("','");
 295     parse_operand(s1, &ops[2]);
 296
 297     switch (token) {
 298     case TOK_ASM_sll:
 299         asm_emit_r(token, (0xC << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
 300         return;
 301     case TOK_ASM_slli:
 302         asm_emit_i(token, (4 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
 303         return;
 304     case TOK_ASM_srl:
 305         asm_emit_r(token, (0xC << 2) | 3 | (4 << 12), &ops[0], &ops[1], &ops[2]);
 306         return;
 307     case TOK_ASM_srli:
 308         asm_emit_i(token, (0x4 << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
 309         return;
 310     case TOK_ASM_sra:
 311         asm_emit_r(token, (0xC << 2) | 3 | (5 << 12) | (32 << 25), &ops[0], &ops[1], &ops[2]);
 312         return;
 313     case TOK_ASM_srai:
 314         asm_emit_i(token, (0x4 << 2) | 3 | (5 << 12) | (16 << 26), &ops[0], &ops[1], &ops[2]);
 315         return;
 316     case TOK_ASM_sllw:
 317         asm_emit_r(token, (0xE << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
 318         return;
 319     case TOK_ASM_slliw:
 320         asm_emit_i(token, (6 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
 321         return;
 322     case TOK_ASM_srlw:
 323         asm_emit_r(token, (0xE << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
 324         return;
 325     case TOK_ASM_srliw:
 326         asm_emit_i(token, (0x6 << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
 327         return;
 328     case TOK_ASM_sraw:
 329         asm_emit_r(token, (0xE << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
 330         return;
 331     case TOK_ASM_sraiw:
 332         asm_emit_i(token, (0x6 << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
 333         return;
 334     default:
 335         expect("shift instruction");
 336     }
 337 }
 338
 339 static void asm_data_processing_opcode(TCCState* s1, int token)
 340 {
 341     Operand ops[3];
 342     parse_operand(s1, &ops[0]);
 343     if (tok == ',')
 344         next();
 345     else
 346         expect("','");
 347     parse_operand(s1, &ops[1]);
 348     if (tok == ',')
 349         next();
 350     else
 351         expect("','");
 352     parse_operand(s1, &ops[2]);
 353
 354     switch (token) {
 355     // Arithmetic (RD,RS1,(RS2|IMM)); R-format, I-format or U-format
 356
 357     case TOK_ASM_add:
 358          asm_emit_r(token, (0xC << 2) | 3, &ops[0], &ops[1], &ops[2]);
 359          return;
 360     case TOK_ASM_addi:
 361          asm_emit_i(token, (4 << 2) | 3, &ops[0], &ops[1], &ops[2]);
 362          return;
 363     case TOK_ASM_sub:
 364          asm_emit_r(token, (0xC << 2) | 3 | (32 << 25), &ops[0], &ops[1], &ops[2]);
 365          return;
 366     case TOK_ASM_addw:
 367          asm_emit_r(token, (0xE << 2) | 3 | (0 << 12), &ops[0], &ops[1], &ops[2]);
 368          return;
 369     case TOK_ASM_addiw: // 64 bit
 370          asm_emit_i(token, (0x6 << 2) | 3 | (0 << 12), &ops[0], &ops[1], &ops[2]);
 371          return;
 372     case TOK_ASM_subw:
 373          asm_emit_r(token, (0xE << 2) | 3 | (0 << 12) | (32 << 25), &ops[0], &ops[1], &ops[2]);
 374          return;
 375
 376     // Logical (RD,RS1,(RS2|IMM)); R-format or I-format
 377
 378     case TOK_ASM_xor:
 379          asm_emit_r(token, (0xC << 2) | 3 | (4 << 12), &ops[0], &ops[1], &ops[2]);
 380          return;
 381     case TOK_ASM_xori:
 382          asm_emit_i(token, (0x4 << 2) | 3 | (4 << 12), &ops[0], &ops[1], &ops[2]);
 383          return;
 384     case TOK_ASM_or:
 385          asm_emit_r(token, (0xC << 2) | 3 | (6 << 12), &ops[0], &ops[1], &ops[2]);
 386          return;
 387     case TOK_ASM_ori:
 388          asm_emit_i(token, (0x4 << 2) | 3 | (6 << 12), &ops[0], &ops[1], &ops[2]);
 389          return;
 390     case TOK_ASM_and:
 391          asm_emit_r(token, (0xC << 2) | 3 | (7 << 12), &ops[0], &ops[1], &ops[2]);
 392          return;
 393     case TOK_ASM_andi:
 394          asm_emit_i(token, (0x4 << 2) | 3 | (7 << 12), &ops[0], &ops[1], &ops[2]);
 395          return;
 396
 397     // Compare (RD,RS1,(RS2|IMM)); R-format or I-format
 398
 399     case TOK_ASM_slt:
 400          asm_emit_r(token, (0xC << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
 401          return;
 402     case TOK_ASM_slti:
 403          asm_emit_i(token, (0x4 << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
 404          return;
 405     case TOK_ASM_sltu:
 406          asm_emit_r(token, (0xC << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
 407          return;
 408     case TOK_ASM_sltiu:
 409          asm_emit_i(token, (0x4 << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
 410          return;
 411     default:
 412          expect("known data processing instruction");
 413     }
 414 }
 415
 416 /* caller: Add funct3 to opcode */
 417 static void asm_emit_s(int token, uint32_t opcode, const Operand* rs1, const Operand* rs2, const Operand* imm)
 418 {
 419     if (rs1->type != OP_REG) {
 420         tcc_error("'%s': Expected first source operand that is a register", get_tok_str(token, NULL));
 421         return;
 422     }
 423     if (rs2->type != OP_REG) {
 424         tcc_error("'%s': Expected second source operand that is a register", get_tok_str(token, NULL));
 425         return;
 426     }
 427     if (imm->type != OP_IM12S) {
 428         tcc_error("'%s': Expected third operand that is an immediate value between 0 and 0xfff", get_tok_str(token, NULL));
 429         return;
 430     }
 431     {
 432         uint16_t v = imm->e.v;
 433         /* S-type instruction:
 434                 31...25 imm[11:5]
 435                 24...20 rs2
 436                 19...15 rs1
 437                 14...12 funct3
 438                 11...7 imm[4:0]
 439                 6...0 opcode
 440         opcode always fixed pos. */
 441         gen_le32(opcode | ENCODE_RS1(rs1->reg) | ENCODE_RS2(rs2->reg) | ((v & 0x1F) << 7) | ((v >> 5) << 25));
 442     }
 443 }
 444
 445 static void asm_data_transfer_opcode(TCCState* s1, int token)
 446 {
 447     Operand ops[3];
 448     parse_operand(s1, &ops[0]);
 449     if (ops[0].type != OP_REG) {
 450         expect("register");
 451         return;
 452     }
 453     if (tok == ',')
 454         next();
 455     else
 456         expect("','");
 457     parse_operand(s1, &ops[1]);
 458     if (ops[1].type != OP_REG) {
 459         expect("register");
 460         return;
 461     }
 462     if (tok == ',')
 463         next();
 464     else
 465         expect("','");
 466     parse_operand(s1, &ops[2]);
 467
 468     switch (token) {
 469     // Loads (RD,RS1,I); I-format
 470
 471     case TOK_ASM_lb:
 472          asm_emit_i(token, (0x0 << 2) | 3, &ops[0], &ops[1], &ops[2]);
 473          return;
 474     case TOK_ASM_lh:
 475          asm_emit_i(token, (0x0 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
 476          return;
 477     case TOK_ASM_lw:
 478          asm_emit_i(token, (0x0 << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
 479          return;
 480     case TOK_ASM_lbu:
 481          asm_emit_i(token, (0x0 << 2) | 3 | (4 << 12), &ops[0], &ops[1], &ops[2]);
 482          return;
 483     case TOK_ASM_lhu:
 484          asm_emit_i(token, (0x0 << 2) | 3 | (5 << 12), &ops[0], &ops[1], &ops[2]);
 485          return;
 486     // 64 bit
 487     case TOK_ASM_ld:
 488          asm_emit_i(token, (0x0 << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
 489          return;
 490     case TOK_ASM_lwu:
 491          asm_emit_i(token, (0x0 << 2) | 3 | (6 << 12), &ops[0], &ops[1], &ops[2]);
 492          return;
 493
 494     // Stores (RS1,RS2,I); S-format
 495
 496     case TOK_ASM_sb:
 497          asm_emit_s(token, (0x8 << 2) | 3 | (0 << 12), &ops[0], &ops[1], &ops[2]);
 498          return;
 499    case TOK_ASM_sh:
 500          asm_emit_s(token, (0x8 << 2) | 3 | (1 << 12), &ops[0], &ops[1], &ops[2]);
 501          return;
 502     case TOK_ASM_sw:
 503          asm_emit_s(token, (0x8 << 2) | 3 | (2 << 12), &ops[0], &ops[1], &ops[2]);
 504          return;
 505     case TOK_ASM_sd:
 506          asm_emit_s(token, (0x8 << 2) | 3 | (3 << 12), &ops[0], &ops[1], &ops[2]);
 507          return;
 508
 509     default:
 510          expect("known data transfer instruction");
 511     }
 512 }
 513
 514 static void asm_branch_opcode(TCCState* s1, int token)
 515 {
 516     // Branch (RS1,RS2,IMM); SB-format
 517     uint32_t opcode = (0x18 << 2) | 3;
 518     uint32_t offset = 0;
 519     Operand ops[3];
 520     parse_operand(s1, &ops[0]);
 521     if (ops[0].type != OP_REG) {
 522         expect("register");
 523         return;
 524     }
 525     if (tok == ',')
 526         next();
 527     else
 528         expect("','");
 529     parse_operand(s1, &ops[1]);
 530     if (ops[1].type != OP_REG) {
 531         expect("register");
 532         return;
 533     }
 534     if (tok == ',')
 535         next();
 536     else
 537         expect("','");
 538     parse_operand(s1, &ops[2]);
 539
 540     if (ops[2].type != OP_IM12S) {
 541         tcc_error("'%s': Expected third operand that is an immediate value between 0 and 0xfff", get_tok_str(token, NULL));
 542         return;
 543     }
 544     offset = ops[2].e.v;
 545     if (offset & 1) {
 546         tcc_error("'%s': Expected third operand that is an even immediate value", get_tok_str(token, NULL));
 547         return;
 548     }
 549
 550     switch (token) {
 551     case TOK_ASM_beq:
 552         opcode |= 0 << 12;
 553         break;
 554     case TOK_ASM_bne:
 555         opcode |= 1 << 12;
 556         break;
 557     case TOK_ASM_blt:
 558         opcode |= 4 << 12;
 559         break;
 560     case TOK_ASM_bge:
 561         opcode |= 5 << 12;
 562         break;
 563     case TOK_ASM_bltu:
 564         opcode |= 6 << 12;
 565         break;
 566     case TOK_ASM_bgeu:
 567         opcode |= 7 << 12;
 568         break;
 569     default:
 570         expect("known branch instruction");
 571     }
 572     asm_emit_opcode(opcode | ENCODE_RS1(ops[0].reg) | ENCODE_RS2(ops[1].reg) | (((offset >> 1) & 0xF) << 8) | (((offset >> 5) & 0x1f) << 25) | (((offset >> 11) & 1) << 7) | (((offset >> 12) & 1) << 31));
 573 }
 574
 575 ST_FUNC void asm_opcode(TCCState *s1, int token)
 576 {
 577     switch (token) {
 578     case TOK_ASM_fence:
 579     case TOK_ASM_fence_i:
 580     case TOK_ASM_scall:
 581     case TOK_ASM_sbreak:
 582     case TOK_ASM_ecall:
 583     case TOK_ASM_ebreak:
 584     case TOK_ASM_mrts:
 585     case TOK_ASM_mrth:
 586     case TOK_ASM_hrts:
 587     case TOK_ASM_wfi:
 588         asm_nullary_opcode(s1, token);
 589         return;
 590
 591     case TOK_ASM_rdcycle:
 592     case TOK_ASM_rdcycleh:
 593     case TOK_ASM_rdtime:
 594     case TOK_ASM_rdtimeh:
 595     case TOK_ASM_rdinstret:
 596     case TOK_ASM_rdinstreth:
 597         asm_unary_opcode(s1, token);
 598         return;
 599
 600     case TOK_ASM_lui:
 601     case TOK_ASM_auipc:
 602         asm_binary_opcode(s1, token);
 603         return;
 604
 605     case TOK_ASM_sll:
 606     case TOK_ASM_slli:
 607     case TOK_ASM_srl:
 608     case TOK_ASM_srli:
 609     case TOK_ASM_sra:
 610     case TOK_ASM_srai:
 611     case TOK_ASM_sllw:
 612     case TOK_ASM_slld:
 613     case TOK_ASM_slliw:
 614     case TOK_ASM_sllid:
 615     case TOK_ASM_srlw:
 616     case TOK_ASM_srld:
 617     case TOK_ASM_srliw:
 618     case TOK_ASM_srlid:
 619     case TOK_ASM_sraw:
 620     case TOK_ASM_srad:
 621     case TOK_ASM_sraiw:
 622     case TOK_ASM_sraid:
 623         asm_shift_opcode(s1, token);
 624         return;
 625
 626     case TOK_ASM_add:
 627     case TOK_ASM_addi:
 628     case TOK_ASM_sub:
 629     case TOK_ASM_addw:
 630     case TOK_ASM_addd:
 631     case TOK_ASM_addiw:
 632     case TOK_ASM_addid:
 633     case TOK_ASM_subw:
 634     case TOK_ASM_subd:
 635     case TOK_ASM_xor:
 636     case TOK_ASM_xori:
 637     case TOK_ASM_or:
 638     case TOK_ASM_ori:
 639     case TOK_ASM_and:
 640     case TOK_ASM_andi:
 641     case TOK_ASM_slt:
 642     case TOK_ASM_slti:
 643     case TOK_ASM_sltu:
 644     case TOK_ASM_sltiu:
 645         asm_data_processing_opcode(s1, token);
 646
 647     case TOK_ASM_lb:
 648     case TOK_ASM_lh:
 649     case TOK_ASM_lw:
 650     case TOK_ASM_lbu:
 651     case TOK_ASM_lhu:
 652     case TOK_ASM_ld:
 653     case TOK_ASM_lwu:
 654     case TOK_ASM_sb:
 655     case TOK_ASM_sh:
 656     case TOK_ASM_sw:
 657     case TOK_ASM_sd:
 658         asm_data_transfer_opcode(s1, token);
 659         return;
 660
 661     case TOK_ASM_beq:
 662     case TOK_ASM_bne:
 663     case TOK_ASM_blt:
 664     case TOK_ASM_bge:
 665     case TOK_ASM_bltu:
 666     case TOK_ASM_bgeu:
 667         asm_branch_opcode(s1, token);
 668         return;
 669
 670     default:
 671         expect("known instruction");
 672     }
 673 }
 674
 675 ST_FUNC void subst_asm_operand(CString *add_str, SValue *sv, int modifier)
 676 {
 677     tcc_error("RISCV64 asm not implemented.");
 678 }
 679
 680 /* generate prolog and epilog code for asm statement */
 681 ST_FUNC void asm_gen_code(ASMOperand *operands, int nb_operands,
 682                          int nb_outputs, int is_output,
 683                          uint8_t *clobber_regs,
 684                          int out_reg)
 685 {
 686 }
 687
 688 ST_FUNC void asm_compute_constraints(ASMOperand *operands,
 689                                     int nb_operands, int nb_outputs,
 690                                     const uint8_t *clobber_regs,
 691                                     int *pout_reg)
 692 {
 693 }
 694
 695 ST_FUNC void asm_clobber(uint8_t *clobber_regs, const char *str)
 696 {
 697     int reg;
 698     TokenSym *ts;
 699
 700     if (!strcmp(str, "memory") ||
 701         !strcmp(str, "cc") ||
 702         !strcmp(str, "flags"))
 703         return;
 704     ts = tok_alloc(str, strlen(str));
 705     reg = asm_parse_regvar(ts->tok);
 706     if (reg == -1) {
 707         tcc_error("invalid clobber register '%s'", str);
 708     }
 709     clobber_regs[reg] = 1;
 710 }
 711
 712 ST_FUNC int asm_parse_regvar (int t)
 713 {
 714     if (t >= TOK_ASM_x0 && t <= TOK_ASM_pc) { /* register name */
 715         switch (t) {
 716             case TOK_ASM_pc:
 717                 return -1; // TODO: Figure out where it can be used after all
 718             default:
 719                 return t - TOK_ASM_x0;
 720         }
 721     } else
 722         return -1;
 723 }
 724
 725 /*************************************************************/
 726 #endif /* ndef TARGET_DEFS_ONLY */