diff --git a/src/assembly.pest b/src/assembly.pest
index 082f0a7..ec8a0f7 100644
--- a/src/assembly.pest
+++ b/src/assembly.pest
@@ -4,7 +4,7 @@ COMMENT = _{ ";" ~ (!NEWLINE ~ ANY)* }
 
 program = { SOI ~ (instruction ~ (NEWLINE | COMMENT)*)* ~ EOI }
 
-instruction = _{ mov | add | sub | mul | div | jmp | cmp | label | org }
+instruction = _{ mov | add | sub | mul | div | jmp | cmp | label | org | inc }
 mov = { "mov" ~ operand ~ "," ~ operand }
 add = { "add" ~ operand ~ "," ~ operand }
 sub = { "sub" ~ operand ~ "," ~ operand }
@@ -13,10 +13,11 @@ div = { "div" ~ operand }
 jmp = { "jmp" ~ name }
 cmp = { "cmp" ~ operand ~ "," ~ operand }
 org = { "org" ~ imm }
+inc = { "inc" ~ operand }
 
 name = { ASCII_ALPHANUMERIC+ }
 label = { ASCII_ALPHANUMERIC+ ~ ":" }
-operand = _{ register | imm | mem }
+operand = _{ register | imm | mem | indirect }
 
 /// Operand should be parsed into reg8/reg16/imm.
 /// So register and number are defined as the silent rule.
@@ -34,4 +35,8 @@ mem8 = { "byte ptr" ~ memx }
 mem16 = { "word ptr" ~ memx | memx }
 memx = @{ "[" ~ imm ~ "]" }
 
+indirect = { "[" ~ base* ~ index* ~ "]" }
+base = { "bx" | "bp" }
+index = { "si" | "di" }
+
 hex = @{ ASCII_DIGIT | "a" | "b" | "c" | "d" | "e" | "f" }
diff --git a/src/inc.rs b/src/inc.rs
new file mode 100644
index 0000000..56d2579
--- /dev/null
+++ b/src/inc.rs
@@ -0,0 +1,72 @@
+use crate::memory::Memory;
+use crate::parser::{imm_to_num, Rule};
+use crate::{cpucontext::CpuContext, define_handler_one};
+use paste::paste;
+use pest::iterators::Pair;
+
+/*
+inc
+1. 1-byte form: inc 16-bit registers
+Opcode bit 7-3: 01000
+bit 2-0: register table
+
+2. 2-byte form: inc 8-bit registers (If operand is 8-bit reg, mod is always 11 and bit 5-3 is 000)
+1-byte Opcode bit 7-1: opcode 1111111
+1-byte W-bit 0: 0-operand is 8-bit
+2-byte mod-bit 7-6: 11
+2-byte Opcode bit 5-3: 000
+2-byte bit 2-0: register table
+
+3. 3-byte form: inc memory location
+1-byte Opcode bit 7-1: 1111111
+1-byte W bit 0: 0-8bit, 1-16bit
+2-byte mod-bit 7-6: 01-8bit contents of next byte of instruction sign extended to 16 bits
+2-byte Opcode 5-3: 000
+2-byte r/m 2-0: (base and index register)
+3-byte Displacement 7-0
+
+3. 4-byte form: inc memory location
+1-byte Opcode bit 7-1: 1111111
+1-byte W bit 0: 0-8bit, 1-16bit
+2-byte mod-bit 7-6
+  * 10-indirect addressing mode, use base register and 16bit displacement of next two byte of instruction
+       (next byte->least significant eight bits, byte after that->most sig bits)
+  * 00-direct addressing mode, no use base register, only use 16bit displacement
+2-byte Opcode 5-3: 000
+2-byte r/m 2-0: (base and index register)
+3-byte Displacement 7-0
+4-byte Displacement 15-8
+
+register table
+000 AX AL
+001 CX CL
+010 DX DL
+011 BX BL
+100 SP AH
+101 BP CH
+110 SI DH
+111 DI BH
+
+r/m field | Base register | Index Register
+000       | BX            | SI
+001       | BX            | DI
+010       | BP            | SI
+011       | BP            | DI
+100       | none          | SI
+101       | none          | DI
+110       | BP            | none
+111       | BX            | none
+
+*/
+
+//fn assemble_inc()
+
+define_handler_one!(inc, first, cpu, memory, {
+    match first.as_rule() {
+        Rule::reg16 => {
+            let v = cpu.get_register(first.as_str()).unwrap();
+            cpu.set_register(first.as_str(), v + 1).unwrap();
+        }
+        _ => println!("Not supported operand for org:{:?}", first),
+    }
+});
diff --git a/src/main.rs b/src/main.rs
index b6c2c14..9e28536 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 mod add;
 mod common;
 mod cpucontext;
+mod inc;
 mod memory;
 mod mov;
 mod org;
@@ -48,6 +49,9 @@ impl Hardware8086 {
             parser::Rule::add => {
                 caller_two!(add, self.cpu, self.memory, instruction);
             }
+            parser::Rule::inc => {
+                caller_one!(inc, self.cpu, self.memory, instruction);
+            }
             _ => println!("NOT implemented yet:{}", line),
         }
         println!("After instruction: {:?}", self.cpu);
diff --git a/src/parser.rs b/src/parser.rs
index f5f7abb..fbc2614 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -267,4 +267,13 @@ mod tests {
 
         assert_eq!(Err("Invalid hex number".to_owned()), _imm_to_num("0xghi"));
     }
+
+    #[test]
+    fn test_parser_indirect_addressing() {
+        // todo: add test for indirect addressing mode
+        // inc [bx + si]
+        // inc [bp + di]
+        // inc [si]
+        // ind [di]
+    }
 }