support jmp(mem, T_FAR)

4 files changed, 59 insertions, 2 deletions

diff --git a/readme.md b/readme.md
index 6c9dbc4..8a7f0a3 100644
--- a/readme.md
+++ b/readme.md
@@ -1,6 +1,6 @@
 [![Build Status](https://github.com/herumi/xbyak/actions/workflows/main.yml/badge.svg)](https://github.com/herumi/xbyak/actions/workflows/main.yml)
 
-# Xbyak 6.00 ; JIT assembler for x86(IA32), x64(AMD64, x86-64) by C++
+# Xbyak 6.01 ; JIT assembler for x86(IA32), x64(AMD64, x86-64) by C++
 
 ## Abstract
 
@@ -19,6 +19,7 @@ Use `and_()`, `or_()`, ... instead of `and()`, `or()`.
 If you want to use them, then specify `-fno-operator-names` option to gcc/clang.
 
 ### News
+- add `jmp(mem)`, `call(mem)` `retf` for far absolute indirect jump.
 - vnni instructions such as vpdpbusd supports vex encoding.
 - (break backward compatibility) `push(byte, imm)` (resp. `push(word, imm)`) forces to cast `imm` to 8(resp. 16) bit.
 - (Windows) `#include <winsock2.h>` has been removed from xbyak.h, so add it explicitly if you need it.
@@ -330,6 +331,23 @@ int x;
   mov(eax, ptr[rip + &x]); // throw exception if the difference between &x and current position is larger than 2GiB
 ```
 
+## Far jump
+
+Use `word|dword|qword` instead of `ptr` to specify the address size.
+
+### 32 bit mode
+```
+jmp(word[eax], T_FAR);  // jmp m16:16(FF /5)
+jmp(dword[eax], T_FAR); // jmp m16:32(FF /5)
+```
+
+### 64 bit mode
+```
+jmp(word[eax], T_FAR);  // jmp m16:16(FF /5)
+jmp(dword[rax], T_FAR); // jmp m16:32(FF /5)
+jmp(qword[rax], T_FAR); // jmp m16:64(REX.W FF /5)
+```
+
 ## Code size
 The default max code size is 4096 bytes.
 Specify the size in constructor of `CodeGenerator()` if necessary.
diff --git a/test/jmp.cpp b/test/jmp.cpp
index e9192b2..a9076c3 100644
--- a/test/jmp.cpp
+++ b/test/jmp.cpp
@@ -1383,3 +1383,18 @@ CYBOZU_TEST_AUTO(setDefaultJmpNEAR)
 		}
 	}
 }
+
+CYBOZU_TEST_AUTO(farJmp)
+{
+	struct Code : Xbyak::CodeGenerator {
+		Code()
+		{
+#ifdef XBYAK32
+			jmp(ptr[eax], T_FAR);
+#else
+			jmp(ptr[rax], T_FAR);
+#endif
+		}
+	};
+	CYBOZU_TEST_EXCEPTION(Code code, std::exception);
+}
diff --git a/test/make_nm.cpp b/test/make_nm.cpp
index b797df5..f0503e6 100644
--- a/test/make_nm.cpp
+++ b/test/make_nm.cpp
@@ -701,6 +701,17 @@ class Test {
 #endif
 #endif
 	}
+	void putFarJmp() const
+	{
+#ifdef XBYAK64
+		put("jmp", "word[rax],T_FAR", "far word [rax]");
+		put("jmp", "dword[rax],T_FAR", "far dword [rax]");
+		put("jmp", "qword[rax],T_FAR", "far qword [rax]");
+#else
+		put("jmp", "dword[eax],T_FAR", "far dword [eax]");
+		put("jmp", "word[eax],T_FAR", "far word [eax]");
+#endif
+	}
 	void putMMX1() const
 	{
 		// emms etc
@@ -2530,6 +2541,7 @@ public:
 #else // USE_AVX
 
 		putJmp();
+		putFarJmp();
 
 #ifdef USE_YASM
 
diff --git a/xbyak/xbyak.h b/xbyak/xbyak.h
index 41b5cc0..03be278 100644
--- a/xbyak/xbyak.h
+++ b/xbyak/xbyak.h
@@ -1574,6 +1574,7 @@ public:
 	enum LabelType {
 		T_SHORT,
 		T_NEAR,
+		T_FAR, // far jump
 		T_AUTO // T_SHORT if possible
 	};
 private:
@@ -1887,6 +1888,7 @@ private:
 	template<class T>
 	void opJmp(T& label, LabelType type, uint8_t shortCode, uint8_t longCode, uint8_t longPref)
 	{
+		if (type == T_FAR) XBYAK_THROW(ERR_NOT_SUPPORTED)
 		if (isAutoGrow() && size_ + 16 >= maxSize_) growMemory(); /* avoid splitting code of jmp */
 		size_t offset = 0;
 		if (labelMgr_.getOffset(&offset, label)) { /* label exists */
@@ -1907,6 +1909,7 @@ private:
 	}
 	void opJmpAbs(const void *addr, LabelType type, uint8_t shortCode, uint8_t longCode, uint8_t longPref = 0)
 	{
+		if (type == T_FAR) XBYAK_THROW(ERR_NOT_SUPPORTED)
 		if (isAutoGrow()) {
 			if (!isNEAR(type)) XBYAK_THROW(ERR_ONLY_T_NEAR_IS_SUPPORTED_IN_AUTO_GROW)
 			if (size_ + 16 >= maxSize_) growMemory();
@@ -2474,7 +2477,16 @@ public:
 
 	// set default type of `jmp` of undefined label to T_NEAR
 	void setDefaultJmpNEAR(bool isNear) { isDefaultJmpNEAR_ = isNear; }
-	void jmp(const Operand& op) { opR_ModM(op, BIT, 4, 0xFF, NONE, NONE, true); }
+	void jmp(const Operand& op, LabelType type = T_AUTO)
+	{
+		if (type == T_FAR) {
+			const int bit = (BIT == 32) ? (16|32) : (16|32|64);
+			if (!op.isMEM(bit)) XBYAK_THROW(ERR_NOT_SUPPORTED)
+			opR_ModM(op, BIT, 5, 0xFF, NONE, NONE, false);
+		} else {
+			opR_ModM(op, BIT, 4, 0xFF, NONE, NONE, true);
+		}
+	}
 	void jmp(std::string label, LabelType type = T_AUTO) { opJmp(label, type, 0xEB, 0xE9, 0); }
 	void jmp(const char *label, LabelType type = T_AUTO) { jmp(std::string(label), type); }
 	void jmp(const Label& label, LabelType type = T_AUTO) { opJmp(label, type, 0xEB, 0xE9, 0); }