diff --git a/Makefile b/Makefile
index dffd512c6818eb51b0be0a3c4610ed897417b937..72f9fa90b06528e61b8e0b9956c0db5cddc66467 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@ include Makefile.git
 CC = gcc
 LD = gcc
 INCLUDES  = $(addprefix -I, $(INC_DIR))
-CFLAGS   += -O2 -MMD -Wall -Werror -ggdb3 $(INCLUDES) -D__ISA__=$(ISA) -fomit-frame-pointer
+CFLAGS   += -O2 -MMD -Wall -Werror -ggdb3 $(INCLUDES) -D__ISA__=$(ISA) -D__ISA_$(ISA)__ -fomit-frame-pointer
 
 QEMU_DIFF_PATH = $(NEMU_HOME)/tools/qemu-diff
 QEMU_SO = $(QEMU_DIFF_PATH)/build/$(ISA)-qemu-so
diff --git a/include/common.h b/include/common.h
index a5d8474c3b6a43b8a085c465955e73a0bbdc306d..1937464186c019ef4acd6089e5668aa432604ae7 100644
--- a/include/common.h
+++ b/include/common.h
@@ -4,7 +4,9 @@
 //#define DEBUG
 //#define DIFF_TEST
 
-#define ISA64
+#ifdef __ISA_riscv64__
+# define ISA64
+#endif
 
 #if _SHARE
 // do not enable these features while building a reference design
@@ -22,17 +24,18 @@
 typedef uint8_t bool;
 
 #ifdef ISA64
-typedef uint64_t rtlreg_t;
-
-typedef uint32_t paddr_t;
-typedef uint64_t vaddr_t;
+typedef uint64_t word_t;
+typedef int64_t sword_t;
+#define FMT_WORD "0x%016lx"
 #else
-typedef uint32_t rtlreg_t;
-
-typedef uint32_t paddr_t;
-typedef uint32_t vaddr_t;
+typedef uint32_t word_t;
+typedef int32_t sword_t;
+#define FMT_WORD "0x%08x"
 #endif
 
+typedef word_t rtlreg_t;
+typedef word_t vaddr_t;
+typedef uint32_t paddr_t;
 typedef uint16_t ioaddr_t;
 
 #define false 0
diff --git a/include/cpu/decode.h b/include/cpu/decode.h
index 86b61dce12c19b670ca65f4588844d5239acef4a..f37c33534215dcecd3af68d290ae00c38defc52f 100644
--- a/include/cpu/decode.h
+++ b/include/cpu/decode.h
@@ -12,21 +12,12 @@ enum { OP_TYPE_REG, OP_TYPE_MEM, OP_TYPE_IMM };
 typedef struct {
   uint32_t type;
   int width;
-#ifdef ISA64
-  union {
-    uint64_t reg;
-    rtlreg_t addr;
-    uint64_t imm;
-    int64_t simm;
-  };
-#else
   union {
     uint32_t reg;
     rtlreg_t addr;
-    uint32_t imm;
-    int32_t simm;
+    word_t imm;
+    sword_t simm;
   };
-#endif
   rtlreg_t val;
   char str[OP_STR_SIZE];
 } Operand;
diff --git a/include/device/map.h b/include/device/map.h
index e50801d5d3de3e62eb20b53c774aab9e1db60693..047ce7e0ba0d1a091eb2f85b7080bd5f5c9abd21 100644
--- a/include/device/map.h
+++ b/include/device/map.h
@@ -34,7 +34,7 @@ static inline int find_mapid_by_addr(IOMap *maps, int size, paddr_t addr) {
 void add_pio_map(char *name, ioaddr_t addr, uint8_t *space, int len, io_callback_t callback);
 void add_mmio_map(char *name, paddr_t addr, uint8_t* space, int len, io_callback_t callback);
 
-uint32_t map_read(paddr_t addr, int len, IOMap *map);
-void map_write(paddr_t addr, uint32_t data, int len, IOMap *map);
+word_t map_read(paddr_t addr, int len, IOMap *map);
+void map_write(paddr_t addr, word_t data, int len, IOMap *map);
 
 #endif
diff --git a/include/memory/memory.h b/include/memory/memory.h
index b1ec27a0ababcfdbbb6bc909016b9186731abfed..e70ec9b9ee2c6a781f2aa6fb55b0bcee9b635370 100644
--- a/include/memory/memory.h
+++ b/include/memory/memory.h
@@ -15,26 +15,14 @@ extern uint8_t pmem[];
 
 void register_pmem(paddr_t base);
 
-uint32_t isa_vaddr_read(vaddr_t, int);
-void isa_vaddr_write(vaddr_t, uint32_t, int);
-#ifdef ISA64
-uint64_t isa_vaddr_read64(vaddr_t, int);
-void isa_vaddr_write64(vaddr_t, uint64_t, int);
-#endif
+word_t isa_vaddr_read(vaddr_t, int);
+void isa_vaddr_write(vaddr_t, word_t, int);
 
 #define vaddr_read isa_vaddr_read
 #define vaddr_write isa_vaddr_write
-#ifdef ISA64
-#define vaddr_read64 isa_vaddr_read64
-#define vaddr_write64 isa_vaddr_write64
-#endif
 
-uint32_t paddr_read(paddr_t, int);
-void paddr_write(paddr_t, uint32_t, int);
-#ifdef ISA64
-uint64_t paddr_read64(paddr_t, int);
-void paddr_write64(paddr_t, uint64_t, int);
-#endif
+word_t paddr_read(paddr_t, int);
+void paddr_write(paddr_t, word_t, int);
 
 #define PAGE_SIZE         4096
 #define PAGE_MASK         (PAGE_SIZE - 1)
diff --git a/include/monitor/diff-test.h b/include/monitor/diff-test.h
index 8aef569037382adbc7ee241267be6a2388178605..d17388c84d1b2f8346ed8c92b66cefc9e2dc8681 100644
--- a/include/monitor/diff-test.h
+++ b/include/monitor/diff-test.h
@@ -21,13 +21,8 @@ extern void (*ref_difftest_exec)(uint64_t n);
 
 static inline bool difftest_check_reg(const char *name, vaddr_t pc, rtlreg_t ref, rtlreg_t dut) {
   if (ref != dut) {
-#ifdef ISA64
-    Log("%s is different after executing instruction at pc = 0x%016lx, right = 0x%016lx, wrong = 0x%016lx",
+    Log("%s is different after executing instruction at pc = " FMT_WORD ", right = " FMT_WORD ", wrong = " FMT_WORD,
         name, pc, ref, dut);
-#else
-    Log("%s is different after executing instruction at pc = 0x%08x, right = 0x%08x, wrong = 0x%08x",
-        name, pc, ref, dut);
-#endif
     return false;
   }
   return true;
diff --git a/include/monitor/expr.h b/include/monitor/expr.h
index c2405057afea2a4c70431e37b617ad12813e4d31..0a752a4be126d22f394c915781519b534d468917 100644
--- a/include/monitor/expr.h
+++ b/include/monitor/expr.h
@@ -3,6 +3,6 @@
 
 #include "common.h"
 
-uint32_t expr(char *, bool *);
+word_t expr(char *, bool *);
 
 #endif
diff --git a/include/monitor/watchpoint.h b/include/monitor/watchpoint.h
index 28108041a4d096b9956a3461a1042c5ebfbed02d..6b861a56bd2ccea345fe4c42b35b8ce0fbbf2599 100644
--- a/include/monitor/watchpoint.h
+++ b/include/monitor/watchpoint.h
@@ -10,8 +10,8 @@ typedef struct watchpoint {
   /* TODO: Add more members if necessary */
 
   char *expr;
-  uint32_t new_val;
-  uint32_t old_val;
+  word_t new_val;
+  word_t old_val;
 } WP;
 
 int set_watchpoint(char *e);
diff --git a/include/rtl/rtl.h b/include/rtl/rtl.h
index 3d9ecd9610eaa6e2769645da27f2752559f098dc..9a3abf4708b1b3996d3adbcd6a8c15e1430d90fb 100644
--- a/include/rtl/rtl.h
+++ b/include/rtl/rtl.h
@@ -87,21 +87,11 @@ static inline void interpret_rtl_idiv64_r(rtlreg_t* dest,
 }
 
 static inline void interpret_rtl_lm(rtlreg_t *dest, const rtlreg_t* addr, int len) {
-#ifdef ISA64
-  if (len == 8) 
-    *dest = vaddr_read64(*addr, len);
-  else
-#endif
-    *dest = vaddr_read(*addr, len);
+  *dest = vaddr_read(*addr, len);
 }
 
 static inline void interpret_rtl_sm(const rtlreg_t* addr, const rtlreg_t* src1, int len) {
-#ifdef ISA64
-  if (len == 8) 
-    vaddr_write64(*addr, *src1, len);
-  else
-#endif
-    vaddr_write(*addr, *src1, len);
+  vaddr_write(*addr, *src1, len);
 }
 
 static inline void interpret_rtl_host_lm(rtlreg_t* dest, const void *addr, int len) {
diff --git a/src/cpu/inv.c b/src/cpu/inv.c
index 4afab7e907729ad957b3abafdfc601892f3e2c77..9a53e9083007e3ce55eab708990a8894bb3497d4 100644
--- a/src/cpu/inv.c
+++ b/src/cpu/inv.c
@@ -3,17 +3,10 @@
 void display_inv_msg(vaddr_t pc) {
   extern char isa_logo[];
 
-#ifdef ISA64
   printf("There are two cases which will trigger this unexpected exception:\n"
-      "1. The instruction at PC = 0x%016lx is not implemented.\n"
+      "1. The instruction at PC = " FMT_WORD " is not implemented.\n"
       "2. Something is implemented incorrectly.\n", pc);
-  printf("Find this PC(0x%016lx) in the disassembling result to distinguish which case it is.\n\n", pc);
-#else
-  printf("There are two cases which will trigger this unexpected exception:\n"
-      "1. The instruction at PC = 0x%08x is not implemented.\n"
-      "2. Something is implemented incorrectly.\n", pc);
-  printf("Find this PC(0x%08x) in the disassembling result to distinguish which case it is.\n\n", pc);
-#endif
+  printf("Find this PC(" FMT_WORD ") in the disassembling result to distinguish which case it is.\n\n", pc);
   printf("\33[1;31mIf it is the first case, see\n%s\nfor more details.\n\nIf it is the second case, remember:\n"
       "* The machine is always right!\n"
       "* Every line of untested code is always wrong!\33[0m\n\n", isa_logo);
diff --git a/src/cpu/relop.c b/src/cpu/relop.c
index 8a60e9d94cd070cdf4ed025404fbfd00fc6d0725..aa18f6fac144dbbf32eef57f2228511994691bbb 100644
--- a/src/cpu/relop.c
+++ b/src/cpu/relop.c
@@ -7,10 +7,10 @@ bool interpret_relop(uint32_t relop, const rtlreg_t src1, const rtlreg_t src2) {
     case RELOP_TRUE: return true;
     case RELOP_EQ: return src1 == src2;
     case RELOP_NE: return src1 != src2;
-    case RELOP_LT: return (int32_t)src1 < (int32_t)src2;
-    case RELOP_LE: return (int32_t)src1 <= (int32_t)src2;
-    case RELOP_GT: return (int32_t)src1 > (int32_t)src2;
-    case RELOP_GE: return (int32_t)src1 >= (int32_t)src2;
+    case RELOP_LT: return (sword_t)src1 <  (sword_t)src2;
+    case RELOP_LE: return (sword_t)src1 <= (sword_t)src2;
+    case RELOP_GT: return (sword_t)src1 >  (sword_t)src2;
+    case RELOP_GE: return (sword_t)src1 >= (sword_t)src2;
     case RELOP_LTU: return src1 < src2;
     case RELOP_LEU: return src1 <= src2;
     case RELOP_GTU: return src1 > src2;
diff --git a/src/device/io/map.c b/src/device/io/map.c
index 8f969fd78eb4544a2081bc71bced95d4b777032b..290e485f0d84b469584c96ead9250187e463dbdc 100644
--- a/src/device/io/map.c
+++ b/src/device/io/map.c
@@ -17,35 +17,29 @@ uint8_t* new_space(int size) {
 }
 
 static inline void check_bound(IOMap *map, paddr_t addr) {
-#ifdef ISA64
   Assert(map != NULL && addr <= map->high && addr >= map->low,
-      "address (0x%08x) is out of bound {%s} [0x%08x, 0x%08x] at pc = 0x%016lx",
+      "address (0x%08x) is out of bound {%s} [0x%08x, 0x%08x] at pc = " FMT_WORD,
       addr, (map ? map->name : "???"), (map ? map->low : 0), (map ? map->high : 0), cpu.pc);
-#else
-  Assert(map != NULL && addr <= map->high && addr >= map->low,
-      "address (0x%08x) is out of bound {%s} [0x%08x, 0x%08x] at pc = 0x%08x",
-      addr, (map ? map->name : "???"), (map ? map->low : 0), (map ? map->high : 0), cpu.pc);
-#endif
 }
 
-static inline void invoke_callback(io_callback_t c, uint32_t offset, int len, bool is_write) {
+static inline void invoke_callback(io_callback_t c, paddr_t offset, int len, bool is_write) {
   if (c != NULL) { c(offset, len, is_write); }
 }
 
-uint32_t map_read(paddr_t addr, int len, IOMap *map) {
-  assert(len >= 1 && len <= 4);
+word_t map_read(paddr_t addr, int len, IOMap *map) {
+  assert(len >= 1 && len <= 8);
   check_bound(map, addr);
-  uint32_t offset = addr - map->low;
+  paddr_t offset = addr - map->low;
   invoke_callback(map->callback, offset, len, false); // prepare data to read
 
-  uint32_t data = *(uint32_t *)(map->space + offset) & (~0u >> ((4 - len) << 3));
+  word_t data = *(word_t *)(map->space + offset) & (~0u >> ((8 - len) << 3));
   return data;
 }
 
-void map_write(paddr_t addr, uint32_t data, int len, IOMap *map) {
-  assert(len >= 1 && len <= 4);
+void map_write(paddr_t addr, word_t data, int len, IOMap *map) {
+  assert(len >= 1 && len <= 8);
   check_bound(map, addr);
-  uint32_t offset = addr - map->low;
+  paddr_t offset = addr - map->low;
 
   memcpy(map->space + offset, &data, len);
 
diff --git a/src/isa/mips32/decode.c b/src/isa/mips32/decode.c
index d1c7b0f366d72b1633295e27cb486b8bafe92483..85654fda89854a7264b309b8b9ffc908832b48e1 100644
--- a/src/isa/mips32/decode.c
+++ b/src/isa/mips32/decode.c
@@ -70,7 +70,7 @@ make_DHelper(st) {
 }
 
 make_DHelper(B) {
-  int32_t offset = (decinfo.isa.instr.simm << 2);
+  sword_t offset = (decinfo.isa.instr.simm << 2);
   decinfo.jmp_pc = cpu.pc + offset + 4;
   decinfo.seq_pc += 4; // skip the delay slot
 
diff --git a/src/isa/mips32/mmu.c b/src/isa/mips32/mmu.c
index abe8f070bfd36e7d483def10e7a98760562954d5..48cb932904cb89f7e71176281becceb56dd44241 100644
--- a/src/isa/mips32/mmu.c
+++ b/src/isa/mips32/mmu.c
@@ -107,10 +107,10 @@ static inline paddr_t va2pa(vaddr_t addr, bool write) {
   return addr;
 }
 
-uint32_t isa_vaddr_read(vaddr_t addr, int len) {
+word_t isa_vaddr_read(vaddr_t addr, int len) {
   return paddr_read(va2pa(addr, false), len);
 }
 
-void isa_vaddr_write(vaddr_t addr, uint32_t data, int len) {
+void isa_vaddr_write(vaddr_t addr, word_t data, int len) {
   paddr_write(va2pa(addr, true), data, len);
 }
diff --git a/src/isa/mips32/reg.c b/src/isa/mips32/reg.c
index 634d8da0f5a53e6fe0ace901505f31333a50041f..38af3384468bb9df2344bd803482400291e64b2f 100644
--- a/src/isa/mips32/reg.c
+++ b/src/isa/mips32/reg.c
@@ -18,7 +18,7 @@ void isa_reg_display() {
   printf("pc: 0x%08x\n", cpu.pc);
 }
 
-uint32_t isa_reg_str2val(const char *s, bool *success) {
+word_t isa_reg_str2val(const char *s, bool *success) {
   int i;
   *success = true;
   for (i = 0; i < 32; i ++) {
diff --git a/src/isa/riscv32/decode.c b/src/isa/riscv32/decode.c
index 2f5614ab667ecd99940d93cc9c3bf4ddd64c829e..8d84e53c4e0cc1b934f99f6f81dd1a41451f7547 100644
--- a/src/isa/riscv32/decode.c
+++ b/src/isa/riscv32/decode.c
@@ -42,7 +42,7 @@ make_DHelper(U) {
 }
 
 make_DHelper(J) {
-  int32_t offset = (decinfo.isa.instr.simm20 << 20) | (decinfo.isa.instr.imm19_12 << 12) |
+  sword_t offset = (decinfo.isa.instr.simm20 << 20) | (decinfo.isa.instr.imm19_12 << 12) |
     (decinfo.isa.instr.imm11_ << 11) | (decinfo.isa.instr.imm10_1 << 1);
   decinfo.jmp_pc = cpu.pc + offset;
   decode_op_i(id_src, decinfo.jmp_pc, true);
@@ -52,7 +52,7 @@ make_DHelper(J) {
 }
 
 make_DHelper(B) {
-  int32_t offset = (decinfo.isa.instr.simm12 << 12) | (decinfo.isa.instr.imm11 << 11) |
+  sword_t offset = (decinfo.isa.instr.simm12 << 12) | (decinfo.isa.instr.imm11 << 11) |
     (decinfo.isa.instr.imm10_5 << 5) | (decinfo.isa.instr.imm4_1 << 1);
   decinfo.jmp_pc = cpu.pc + offset;
   decode_op_i(id_dest, decinfo.jmp_pc, true);
@@ -75,7 +75,7 @@ make_DHelper(ld) {
 
 make_DHelper(st) {
   decode_op_r(id_src, decinfo.isa.instr.rs1, true);
-  int32_t simm = (decinfo.isa.instr.simm11_5 << 5) | decinfo.isa.instr.imm4_0;
+  sword_t simm = (decinfo.isa.instr.simm11_5 << 5) | decinfo.isa.instr.imm4_0;
   decode_op_i(id_src2, simm, true);
 
   print_Dop(id_src->str, OP_STR_SIZE, "%d(%s)", id_src2->val, reg_name(id_src->reg, 4));
diff --git a/src/isa/riscv32/mmu.c b/src/isa/riscv32/mmu.c
index c963d86bedb8449446984667c2e1dbcc22f7c69b..b854b6609b7e89be9daf8218911f1aab69a539ed 100644
--- a/src/isa/riscv32/mmu.c
+++ b/src/isa/riscv32/mmu.c
@@ -57,12 +57,12 @@ static inline paddr_t page_translate(vaddr_t addr, bool is_write) {
   return page_walk(addr, is_write) | (addr & PAGE_MASK);
 }
 
-uint32_t isa_vaddr_read(vaddr_t addr, int len) {
+word_t isa_vaddr_read(vaddr_t addr, int len) {
   paddr_t paddr = (cpu.satp.mode ? page_translate(addr, false) : addr);
   return paddr_read(paddr, len);
 }
 
-void isa_vaddr_write(vaddr_t addr, uint32_t data, int len) {
+void isa_vaddr_write(vaddr_t addr, word_t data, int len) {
   paddr_t paddr = (cpu.satp.mode ? page_translate(addr, true) : addr);
   paddr_write(paddr, data, len);
 }
diff --git a/src/isa/riscv32/reg.c b/src/isa/riscv32/reg.c
index 4cc1df7f88cd762d8685eace168bf823c7733a38..266fe28f12c07540c1f8ddb95e39f71192e8595b 100644
--- a/src/isa/riscv32/reg.c
+++ b/src/isa/riscv32/reg.c
@@ -18,7 +18,7 @@ void isa_reg_display() {
   printf("pc: 0x%08x\n", cpu.pc);
 }
 
-uint32_t isa_reg_str2val(const char *s, bool *success) {
+word_t isa_reg_str2val(const char *s, bool *success) {
   int i;
   *success = true;
   for (i = 0; i < 32; i ++) {
diff --git a/src/isa/riscv64/decode.c b/src/isa/riscv64/decode.c
index e9b133bbc00f735f3e9347358b071fc6aecd92fb..15967fbbf95f8d8b9b7e92925ce4fb2c995e74ca 100644
--- a/src/isa/riscv64/decode.c
+++ b/src/isa/riscv64/decode.c
@@ -42,7 +42,7 @@ make_DHelper(U) {
 }
 
 make_DHelper(J) {
-  int32_t offset = (decinfo.isa.instr.simm20 << 20) | (decinfo.isa.instr.imm19_12 << 12) |
+  sword_t offset = (decinfo.isa.instr.simm20 << 20) | (decinfo.isa.instr.imm19_12 << 12) |
     (decinfo.isa.instr.imm11_ << 11) | (decinfo.isa.instr.imm10_1 << 1);
   decinfo.jmp_pc = cpu.pc + offset;
   decode_op_i(id_src, decinfo.jmp_pc, true);
@@ -52,7 +52,7 @@ make_DHelper(J) {
 }
 
 make_DHelper(B) {
-  int32_t offset = (decinfo.isa.instr.simm12 << 12) | (decinfo.isa.instr.imm11 << 11) |
+  sword_t offset = (decinfo.isa.instr.simm12 << 12) | (decinfo.isa.instr.imm11 << 11) |
     (decinfo.isa.instr.imm10_5 << 5) | (decinfo.isa.instr.imm4_1 << 1);
   decinfo.jmp_pc = cpu.pc + offset;
   decode_op_i(id_dest, decinfo.jmp_pc, true);
@@ -75,7 +75,7 @@ make_DHelper(ld) {
 
 make_DHelper(st) {
   decode_op_r(id_src, decinfo.isa.instr.rs1, true);
-  int32_t simm = (decinfo.isa.instr.simm11_5 << 5) | decinfo.isa.instr.imm4_0;
+  sword_t simm = (decinfo.isa.instr.simm11_5 << 5) | decinfo.isa.instr.imm4_0;
   decode_op_i(id_src2, simm, true);
 
   print_Dop(id_src->str, OP_STR_SIZE, "%ld(%s)", id_src2->val, reg_name(id_src->reg, 4));
diff --git a/src/isa/riscv64/exec/compute.c b/src/isa/riscv64/exec/compute.c
index 4162edd273b27f11eb97f9f36c3ec01ec414a659..0f53a4ada2755f6aa91f23960146838cfad81efb 100644
--- a/src/isa/riscv64/exec/compute.c
+++ b/src/isa/riscv64/exec/compute.c
@@ -15,11 +15,7 @@ make_EHelper(sub) {
 }
 
 make_EHelper(sll) {
-#ifdef ISA64
   rtl_andi(&id_src2->val, &id_src2->val, 0x3f);
-#else
-  rtl_andi(&id_src2->val, &id_src2->val, 0x1f);
-#endif
   rtl_shl(&s0, &id_src->val, &id_src2->val);
   rtl_sr(id_dest->reg, &s0, 4);
 
@@ -27,11 +23,7 @@ make_EHelper(sll) {
 }
 
 make_EHelper(srl) {
-#ifdef ISA64
   rtl_andi(&id_src2->val, &id_src2->val, 0x3f);
-#else
-  rtl_andi(&id_src2->val, &id_src2->val, 0x1f);
-#endif
 
   if (decinfo.isa.instr.funct7 == 32) {
     // sra
@@ -145,4 +137,4 @@ make_EHelper(srlw) {
 
 make_EHelper(sraw) {
   exec_srlw(NULL);
-}
\ No newline at end of file
+}
diff --git a/src/isa/riscv64/exec/exec.c b/src/isa/riscv64/exec/exec.c
index cf6f501ec728088eea155c9b4ad26eb04d2ffc0e..6b06e8af5f81feb8ca5120a193b9147d0007fb92 100644
--- a/src/isa/riscv64/exec/exec.c
+++ b/src/isa/riscv64/exec/exec.c
@@ -2,7 +2,7 @@
 #include "all-instr.h"
 
 static OpcodeEntry load_table [8] = {
-  EXW(lds, 1), EXW(lds, 2), EXW(ld, 4), EXW(ld, 8), EXW(ld, 1), EXW(ld, 2), EMPTY, EMPTY
+  EXW(lds, 1), EXW(lds, 2), EXW(lds, 4), EXW(ld, 8), EXW(ld, 1), EXW(ld, 2), EXW(ld, 4), EMPTY
 };
 
 static make_EHelper(load) {
diff --git a/src/isa/riscv64/exec/ldst.c b/src/isa/riscv64/exec/ldst.c
index 13f04649aa893a540b9f6da30b6b1a1c58ed1caa..0778bbd3505cb85ba0fb7eee452a1056986cc697 100644
--- a/src/isa/riscv64/exec/ldst.c
+++ b/src/isa/riscv64/exec/ldst.c
@@ -2,18 +2,11 @@
 
 make_EHelper(ld) {
   rtl_lm(&s0, &id_src->addr, decinfo.width);
-
-#ifdef ISA64
-  if (decinfo.width == 4) {  // for lw
-    rtl_sext(&s0, &s0, 4);
-  }
-#endif
-
-  rtl_sr(id_dest->reg, &s0, 4);
+  rtl_sr(id_dest->reg, &s0, 0);
 
   switch (decinfo.width) {
     case 8: print_asm_template2(ld); break;
-    case 4: print_asm_template2(lw); break;
+    case 4: print_asm_template2(lwu); break;
     case 2: print_asm_template2(lhu); break;
     case 1: print_asm_template2(lbu); break;
     default: assert(0);
@@ -24,9 +17,10 @@ make_EHelper(ld) {
 make_EHelper(lds) {
   rtl_lm(&s0, &id_src->addr, decinfo.width);
   rtl_sext(&s0, &s0, decinfo.width);
-  rtl_sr(id_dest->reg, &s0, 4);
+  rtl_sr(id_dest->reg, &s0, 0);
 
   switch (decinfo.width) {
+    case 4: print_asm_template2(lw); break;
     case 2: print_asm_template2(lh); break;
     case 1: print_asm_template2(lb); break;
     default: assert(0);
diff --git a/src/isa/riscv64/mmu.c b/src/isa/riscv64/mmu.c
index 09ad02ef48e98f951d30ce185d7cfc983ad3793f..5eec5dc19a0c1b85eefea0a82f12357f0e8e083b 100644
--- a/src/isa/riscv64/mmu.c
+++ b/src/isa/riscv64/mmu.c
@@ -58,22 +58,12 @@ static inline paddr_t page_translate(vaddr_t addr, bool is_write) {
   return page_walk(addr, is_write) | (addr & PAGE_MASK);
 }
 
-uint32_t isa_vaddr_read(vaddr_t addr, int len) {
+word_t isa_vaddr_read(vaddr_t addr, int len) {
   paddr_t paddr = (cpu.satp.mode ? page_translate(addr, false) : addr);
   return paddr_read(paddr, len);
 }
 
-void isa_vaddr_write(vaddr_t addr, uint32_t data, int len) {
+void isa_vaddr_write(vaddr_t addr, word_t data, int len) {
   paddr_t paddr = (cpu.satp.mode ? page_translate(addr, true) : addr);
   paddr_write(paddr, data, len);
 }
-
-uint64_t isa_vaddr_read64(vaddr_t addr, int len) {
-  paddr_t paddr = (cpu.satp.mode ? page_translate(addr, false) : addr);
-  return paddr_read64(paddr, len);
-}
-
-void isa_vaddr_write64(vaddr_t addr, uint64_t data, int len) {
-  paddr_t paddr = (cpu.satp.mode ? page_translate(addr, true) : addr);
-  paddr_write64(paddr, data, len);
-}
\ No newline at end of file
diff --git a/src/isa/x86/decode/modrm.c b/src/isa/x86/decode/modrm.c
index c550aca9f0f2a95a1226f54bdbbd32f3724ecb7f..1ae2f79cfbc62705fbe653de6ef2835b40834f08 100644
--- a/src/isa/x86/decode/modrm.c
+++ b/src/isa/x86/decode/modrm.c
@@ -3,7 +3,7 @@
 void load_addr(vaddr_t *pc, ModR_M *m, Operand *rm) {
   assert(m->mod != 3);
 
-  int32_t disp = 0;
+  sword_t disp = 0;
   int disp_size = 4;
   int base_reg = -1, index_reg = -1, scale = 0;
   rtl_li(&s0, 0);
diff --git a/src/isa/x86/mmu.c b/src/isa/x86/mmu.c
index 87b457412c74904976fcb962f11095e6dd34f4e6..76dca3ec6a51f30180f9aa072517307726602aa0 100644
--- a/src/isa/x86/mmu.c
+++ b/src/isa/x86/mmu.c
@@ -44,8 +44,8 @@ static inline paddr_t page_translate(vaddr_t addr, bool is_write) {
   return page_walk(addr, is_write) | (addr & PAGE_MASK);
 }
 
-uint32_t isa_vaddr_read(vaddr_t addr, int len) {
-  uint32_t data;
+word_t isa_vaddr_read(vaddr_t addr, int len) {
+  word_t data;
   if (cpu.cr0.paging) {
     paddr_t paddr = page_translate(addr, false);
     uint32_t remain_byte = PAGE_SIZE - (addr & PAGE_MASK);
@@ -67,7 +67,7 @@ uint32_t isa_vaddr_read(vaddr_t addr, int len) {
   return data;
 }
 
-void isa_vaddr_write(vaddr_t addr, uint32_t data, int len) {
+void isa_vaddr_write(vaddr_t addr, word_t data, int len) {
   if (cpu.cr0.paging) {
     paddr_t paddr = page_translate(addr, true);
     uint32_t remain_byte = PAGE_SIZE - (addr & PAGE_MASK);
diff --git a/src/isa/x86/reg.c b/src/isa/x86/reg.c
index acae4fd4a81e1960b4e4e724f21d5863473244f6..5727e51e75422f51519d5aa3e46964bf88010f26 100644
--- a/src/isa/x86/reg.c
+++ b/src/isa/x86/reg.c
@@ -8,8 +8,8 @@ const char *regsb[] = {"al", "cl", "dl", "bl", "ah", "ch", "dh", "bh"};
 
 void reg_test() {
   srand(time(0));
-  uint32_t sample[8];
-  uint32_t pc_sample = rand();
+  word_t sample[8];
+  word_t pc_sample = rand();
   cpu.pc = pc_sample;
 
   int i;
@@ -48,7 +48,7 @@ void isa_reg_display() {
   printf("pc: 0x%08x\n", cpu.pc);
 }
 
-uint32_t isa_reg_str2val(const char *s, bool *success) {
+word_t isa_reg_str2val(const char *s, bool *success) {
   int i;
   *success = true;
   for (i = 0; i < 8; i ++) {
diff --git a/src/memory/memory.c b/src/memory/memory.c
index ea970e1ab77e95ab9ffc91591229317b82cbf48f..36bb437d26bc3a333f3164c8e9fdc911d7766b06 100644
--- a/src/memory/memory.c
+++ b/src/memory/memory.c
@@ -20,46 +20,22 @@ IOMap* fetch_mmio_map(paddr_t addr);
 
 /* Memory accessing interfaces */
 
-uint32_t paddr_read(paddr_t addr, int len) {
+word_t paddr_read(paddr_t addr, int len) {
   if (map_inside(&pmem_map, addr)) {
-    uint32_t offset = addr - pmem_map.low;
-    return *(uint32_t *)(pmem + offset) & (~0u >> ((4 - len) << 3));
+    paddr_t offset = addr - pmem_map.low;
+    return *(uint64_t *)(pmem + offset) & (~0LLu >> ((8 - len) << 3));
   }
   else {
     return map_read(addr, len, fetch_mmio_map(addr));
   }
 }
 
-void paddr_write(paddr_t addr, uint32_t data, int len) {
+void paddr_write(paddr_t addr, word_t data, int len) {
   if (map_inside(&pmem_map, addr)) {
-    uint32_t offset = addr - pmem_map.low;
+    paddr_t offset = addr - pmem_map.low;
     memcpy(pmem + offset, &data, len);
   }
   else {
     return map_write(addr, data, len, fetch_mmio_map(addr));
   }
 }
-
-uint64_t paddr_read64(paddr_t addr, int len) {
-  if (map_inside(&pmem_map, addr)) {
-    uint64_t offset = addr - pmem_map.low;
-    return *(uint64_t *)(pmem + offset);
-  }
-  else {
-    // TODO
-    printf("TODO");
-    return 0;
-  }
-}
-
-void paddr_write64(paddr_t addr, uint64_t data, int len) {
-  if (map_inside(&pmem_map, addr)) {
-    uint64_t offset = addr - pmem_map.low;
-    memcpy(pmem + offset, &data, len);
-  }
-  else {
-    // TODO
-    printf("TODO");
-    return;
-  }
-}
\ No newline at end of file
diff --git a/src/monitor/cpu-exec.c b/src/monitor/cpu-exec.c
index 54e7fb96211f8e3852d49b6195c2551486544b9f..4b24b118b68fb0b6a250fe3b811146a70c03b0f5 100644
--- a/src/monitor/cpu-exec.c
+++ b/src/monitor/cpu-exec.c
@@ -61,11 +61,7 @@ void cpu_exec(uint64_t n) {
     /* TODO: check watchpoints here. */
     WP *wp = scan_watchpoint();
     if(wp != NULL) {
-#ifdef ISA64
-      printf("\n\nHint watchpoint %d at address 0x%016lx, expr = %s\n", wp->NO, ori_pc, wp->expr);
-#else
-      printf("\n\nHint watchpoint %d at address 0x%08x, expr = %s\n", wp->NO, ori_pc, wp->expr);
-#endif
+      printf("\n\nHint watchpoint %d at address " FMT_WORD ", expr = %s\n", wp->NO, ori_pc, wp->expr);
       printf("old value = %#08x\nnew value = %#08x\n", wp->old_val, wp->new_val);
       wp->old_val = wp->new_val;
       return;
@@ -87,17 +83,10 @@ void cpu_exec(uint64_t n) {
     case NEMU_RUNNING: nemu_state.state = NEMU_STOP; break;
 
     case NEMU_END: case NEMU_ABORT:
-#ifdef ISA64
-      _Log("nemu: %s\33[0m at pc = 0x%016lx\n\n",
+      _Log("nemu: %s\33[0m at pc = " FMT_WORD "\n\n",
           (nemu_state.state == NEMU_ABORT ? "\33[1;31mABORT" :
            (nemu_state.halt_ret == 0 ? "\33[1;32mHIT GOOD TRAP" : "\33[1;31mHIT BAD TRAP")),
           nemu_state.halt_pc);
-#else
-      _Log("nemu: %s\33[0m at pc = 0x%08x\n\n",
-          (nemu_state.state == NEMU_ABORT ? "\33[1;31mABORT" :
-           (nemu_state.halt_ret == 0 ? "\33[1;32mHIT GOOD TRAP" : "\33[1;31mHIT BAD TRAP")),
-          nemu_state.halt_pc);
-#endif
       monitor_statistic();
   }
 }
diff --git a/src/monitor/debug/expr.c b/src/monitor/debug/expr.c
index f870f01fb04c30413f952082234c23f73f15eede..2eca87e058d2b8fb3277655ce3dd26c1999f3edc 100644
--- a/src/monitor/debug/expr.c
+++ b/src/monitor/debug/expr.c
@@ -173,7 +173,7 @@ static int find_dominated_op(int s, int e, bool *success) {
   return dominated_op;
 }
 
-uint32_t isa_reg_str2val(const char*, bool *);
+word_t isa_reg_str2val(const char*, bool *);
 
 static rtlreg_t eval(int s, int e, bool *success) {
   if (s > e) {
@@ -236,7 +236,7 @@ static rtlreg_t eval(int s, int e, bool *success) {
   }
 }
 
-rtlreg_t expr(char *e, bool *success) {
+word_t expr(char *e, bool *success) {
   if (!make_token(e)) {
     *success = false;
     return 0;
diff --git a/src/monitor/debug/log.c b/src/monitor/debug/log.c
index d917a858471ed642fbfe105d0099f24194fa62a1..66e606fc2cfcae6e90f140bcc38d818f49cc1b33 100644
--- a/src/monitor/debug/log.c
+++ b/src/monitor/debug/log.c
@@ -22,13 +22,8 @@ void strcatf(char *buf, const char *fmt, ...) {
 }
 
 void asm_print(vaddr_t ori_pc, int instr_len, bool print_flag) {
-#ifdef ISA64
-  snprintf(tempbuf, sizeof(tempbuf), "%016lx:   %s%*.s%s", ori_pc, log_bytebuf,
+  snprintf(tempbuf, sizeof(tempbuf), FMT_WORD ":   %s%*.s%s", ori_pc, log_bytebuf,
       50 - (12 + 3 * instr_len), "", log_asmbuf);
-#else
-  snprintf(tempbuf, sizeof(tempbuf), "%8x:   %s%*.s%s", ori_pc, log_bytebuf,
-      50 - (12 + 3 * instr_len), "", log_asmbuf);
-#endif
   log_write("%s\n", tempbuf);
   if (print_flag) {
     puts(tempbuf);
diff --git a/src/monitor/debug/ui.c b/src/monitor/debug/ui.c
index 11fd05063455a80133d5f4bd53f9af6051cd9792..9e3db05982f2ccd6375f98eb22a821c1415154b6 100644
--- a/src/monitor/debug/ui.c
+++ b/src/monitor/debug/ui.c
@@ -88,13 +88,8 @@ static int cmd_d(char *args) {
 static int cmd_p(char *args) {
   if (args != NULL) {
     bool success;
-#ifdef ISA64
-    uint64_t r = expr(args, &success);
-    if(success) { printf("0x%lx\n", r); }
-#else
-    uint32_t r = expr(args, &success);
-    if(success) { printf("%d\n", r); }
-#endif
+    word_t r = expr(args, &success);
+    if(success) { printf(FMT_WORD "\n", r); }
     else { printf("Bad expression\n"); }
   }
   return 0;
@@ -127,14 +122,10 @@ static int cmd_x(char *args) {
     if (success) {
       for (i = 0; i < n; i ++) {
         if (i % 4 == 0) {
-#ifdef ISA64
-          printf("0x%016lx: ", addr);
-#else
-          printf("0x%08x: ", addr);
-#endif
+          printf(FMT_WORD ": ", addr);
         }
 
-        printf("0x%08x ", vaddr_read(addr, 4));
+        printf("0x%08x ", (uint32_t)vaddr_read(addr, 4));
         addr += 4;
         if (i % 4 == 3) {
           printf("\n");
diff --git a/src/monitor/debug/watchpoint.c b/src/monitor/debug/watchpoint.c
index e64a7d32173d1ecf633a1f7aec5a94f268ee0f5f..a4b869a1d67e26f2d41aeed178c0819e4b7773a6 100644
--- a/src/monitor/debug/watchpoint.c
+++ b/src/monitor/debug/watchpoint.c
@@ -36,9 +36,8 @@ static void free_WP(WP *p) {
 }
 
 int set_watchpoint(char *e) {
-  uint32_t val;
   bool success;
-  val = expr(e, &success);
+  word_t val = expr(e, &success);
   if (!success) return -1;
 
   WP *p = new_WP();
@@ -74,7 +73,7 @@ void list_watchpoint() {
   printf("%8s\t%8s\t%8s\n", "NO", "Address", "Enable");
   WP *p;
   for (p = head; p != NULL; p = p->next) {
-    printf("%8d\t%s\t%#08x\n", p->NO, p->expr, p->old_val);
+    printf("%8d\t%s\t" FMT_WORD "\n", p->NO, p->expr, p->old_val);
   }
 }
 
diff --git a/src/monitor/diff-test/diff-test.c b/src/monitor/diff-test/diff-test.c
index 76ae5d95f9ce845fd100891947e4297bbdc88d0e..115fb135ff691eb273fbf0996145711f5c0eca09 100644
--- a/src/monitor/diff-test/diff-test.c
+++ b/src/monitor/diff-test/diff-test.c
@@ -95,11 +95,7 @@ void difftest_step(vaddr_t ori_pc, vaddr_t next_pc) {
     }
     skip_dut_nr_instr --;
     if (skip_dut_nr_instr == 0)
-#ifdef ISA64
-      panic("can not catch up with ref.pc = %lx at pc = %lx", ref_r.pc, ori_pc);
-#else
-      panic("can not catch up with ref.pc = %x at pc = %x", ref_r.pc, ori_pc);
-#endif
+      panic("can not catch up with ref.pc = " FMT_WORD " at pc = " FMT_WORD, ref_r.pc, ori_pc);
     return;
   }