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comparison src/cpu/x86/vm/assembler_x86.cpp @ 3851:95134e034042

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7063629: use cbcond in C2 generated code on T4 Summary: Use new short branch instruction in C2 generated code. Reviewed-by: never
author kvn
date Thu, 11 Aug 2011 12:08:11 -0700
parents de6a837d75cf
children 1af104d6cf99
comparison
equal deleted inserted replaced
3850:6987871cfb9b 3851:95134e034042
1337 prefix(dst); 1337 prefix(dst);
1338 emit_byte(0xFF); 1338 emit_byte(0xFF);
1339 emit_operand(rax, dst); 1339 emit_operand(rax, dst);
1340 } 1340 }
1341 1341
1342 void Assembler::jcc(Condition cc, Label& L, relocInfo::relocType rtype) { 1342 void Assembler::jcc(Condition cc, Label& L, bool maybe_short) {
1343 InstructionMark im(this); 1343 InstructionMark im(this);
1344 relocate(rtype);
1345 assert((0 <= cc) && (cc < 16), "illegal cc"); 1344 assert((0 <= cc) && (cc < 16), "illegal cc");
1346 if (L.is_bound()) { 1345 if (L.is_bound()) {
1347 address dst = target(L); 1346 address dst = target(L);
1348 assert(dst != NULL, "jcc most probably wrong"); 1347 assert(dst != NULL, "jcc most probably wrong");
1349 1348
1350 const int short_size = 2; 1349 const int short_size = 2;
1351 const int long_size = 6; 1350 const int long_size = 6;
1352 intptr_t offs = (intptr_t)dst - (intptr_t)_code_pos; 1351 intptr_t offs = (intptr_t)dst - (intptr_t)_code_pos;
1353 if (rtype == relocInfo::none && is8bit(offs - short_size)) { 1352 if (maybe_short && is8bit(offs - short_size)) {
1354 // 0111 tttn #8-bit disp 1353 // 0111 tttn #8-bit disp
1355 emit_byte(0x70 | cc); 1354 emit_byte(0x70 | cc);
1356 emit_byte((offs - short_size) & 0xFF); 1355 emit_byte((offs - short_size) & 0xFF);
1357 } else { 1356 } else {
1358 // 0000 1111 1000 tttn #32-bit disp 1357 // 0000 1111 1000 tttn #32-bit disp
1397 prefix(adr); 1396 prefix(adr);
1398 emit_byte(0xFF); 1397 emit_byte(0xFF);
1399 emit_operand(rsp, adr); 1398 emit_operand(rsp, adr);
1400 } 1399 }
1401 1400
1402 void Assembler::jmp(Label& L, relocInfo::relocType rtype) { 1401 void Assembler::jmp(Label& L, bool maybe_short) {
1403 if (L.is_bound()) { 1402 if (L.is_bound()) {
1404 address entry = target(L); 1403 address entry = target(L);
1405 assert(entry != NULL, "jmp most probably wrong"); 1404 assert(entry != NULL, "jmp most probably wrong");
1406 InstructionMark im(this); 1405 InstructionMark im(this);
1407 const int short_size = 2; 1406 const int short_size = 2;
1408 const int long_size = 5; 1407 const int long_size = 5;
1409 intptr_t offs = entry - _code_pos; 1408 intptr_t offs = entry - _code_pos;
1410 if (rtype == relocInfo::none && is8bit(offs - short_size)) { 1409 if (maybe_short && is8bit(offs - short_size)) {
1411 emit_byte(0xEB); 1410 emit_byte(0xEB);
1412 emit_byte((offs - short_size) & 0xFF); 1411 emit_byte((offs - short_size) & 0xFF);
1413 } else { 1412 } else {
1414 emit_byte(0xE9); 1413 emit_byte(0xE9);
1415 emit_long(offs - long_size); 1414 emit_long(offs - long_size);
1418 // By default, forward jumps are always 32-bit displacements, since 1417 // By default, forward jumps are always 32-bit displacements, since
1419 // we can't yet know where the label will be bound. If you're sure that 1418 // we can't yet know where the label will be bound. If you're sure that
1420 // the forward jump will not run beyond 256 bytes, use jmpb to 1419 // the forward jump will not run beyond 256 bytes, use jmpb to
1421 // force an 8-bit displacement. 1420 // force an 8-bit displacement.
1422 InstructionMark im(this); 1421 InstructionMark im(this);
1423 relocate(rtype);
1424 L.add_patch_at(code(), locator()); 1422 L.add_patch_at(code(), locator());
1425 emit_byte(0xE9); 1423 emit_byte(0xE9);
1426 emit_long(0); 1424 emit_long(0);
1427 } 1425 }
1428 } 1426 }