diff --git a/src/z80_flags.inc.c b/src/z80_flags.inc.c
index c966be1..d64cf35 100644
--- a/src/z80_flags.inc.c
+++ b/src/z80_flags.inc.c
@@ -146,6 +146,17 @@ static inline void set_flags_bitshift(Z80 *z80, uint8_t res, uint8_t bit)
         SIGN(res), 0xFF);
 }
 
+/*
+    Set the flags for a NEG instruction.
+*/
+static inline void set_flags_neg(Z80 *z80)
+{
+    uint8_t val = z80->regs.a;
+    uint8_t res = -val;
+    set_flags(z80, CARRY(0, -, val), SUB, OV_SUB(0, val, res), F3(res),
+        HALF(0, -, val), F5(res), ZERO(res), SIGN(res), 0xFF);
+}
+
 #undef POS
 #undef NEG
 #undef CARRY
diff --git a/src/z80_ops.inc.c b/src/z80_ops.inc.c
index e352916..3003872 100644
--- a/src/z80_ops.inc.c
+++ b/src/z80_ops.inc.c
@@ -335,6 +335,7 @@ static uint8_t z80_inst_ld_sp_hl(Z80 *z80, uint8_t opcode)
 {
     (void) opcode;
     z80->regs.sp = z80->regs.hl;
+    z80->regs.pc++;
     return 6;
 }
 
@@ -346,6 +347,7 @@ static uint8_t z80_inst_ld_sp_ixy(Z80 *z80, uint8_t opcode)
 {
     (void) opcode;
     *z80->regs.ixy = z80->regs.hl;
+    z80->regs.pc++;
     return 10;
 }
 
@@ -1119,7 +1121,18 @@ static uint8_t z80_inst_dec_ixy(Z80 *z80, uint8_t opcode)
 
 // TODO: CPL
 
-// TODO: NEG
+/*
+    NEG (0xED44, 0xED4C, 0xED54, 0xED5C, 0xED64, 0xED6C, 0xED74, 0xED7C):
+    Negate A.
+*/
+static uint8_t z80_inst_neg(Z80 *z80, uint8_t opcode)
+{
+    (void) opcode;
+    set_flags_neg(z80);
+    z80->regs.a = -z80->regs.a;
+    z80->regs.pc++;
+    return 8;
+}
 
 // TODO: CCF
 
diff --git a/src/z80_tables.inc.c b/src/z80_tables.inc.c
index a91a452..f94cf72 100644
--- a/src/z80_tables.inc.c
+++ b/src/z80_tables.inc.c
@@ -329,7 +329,7 @@ static DispatchTable instruction_table_extended = {
     [0x41] = z80_inst_out_c_r,
     [0x42] = z80_inst_sbc_hl_ss,
     [0x43] = z80_inst_ld_inn_dd,
-    [0x44] = z80_inst_unimplemented,  // TODO
+    [0x44] = z80_inst_neg,
     [0x45] = z80_inst_retn,
     [0x46] = z80_inst_im,
     [0x47] = z80_inst_ld_i_a,
@@ -337,7 +337,7 @@ static DispatchTable instruction_table_extended = {
     [0x49] = z80_inst_out_c_r,
     [0x4A] = z80_inst_adc_hl_ss,
     [0x4B] = z80_inst_ld_dd_inn,
-    [0x4C] = z80_inst_unimplemented,  // TODO
+    [0x4C] = z80_inst_neg,
     [0x4D] = z80_inst_reti,
     [0x4E] = z80_inst_im,
     [0x4F] = z80_inst_ld_r_a,
@@ -345,7 +345,7 @@ static DispatchTable instruction_table_extended = {
     [0x51] = z80_inst_out_c_r,
     [0x52] = z80_inst_sbc_hl_ss,
     [0x53] = z80_inst_ld_inn_dd,
-    [0x54] = z80_inst_unimplemented,  // TODO
+    [0x54] = z80_inst_neg,
     [0x55] = z80_inst_retn,
     [0x56] = z80_inst_im,
     [0x57] = z80_inst_unimplemented,  // TODO
@@ -353,7 +353,7 @@ static DispatchTable instruction_table_extended = {
     [0x59] = z80_inst_out_c_r,
     [0x5A] = z80_inst_adc_hl_ss,
     [0x5B] = z80_inst_ld_dd_inn,
-    [0x5C] = z80_inst_unimplemented,  // TODO
+    [0x5C] = z80_inst_neg,
     [0x5D] = z80_inst_retn,
     [0x5E] = z80_inst_im,
     [0x5F] = z80_inst_unimplemented,  // TODO
@@ -361,7 +361,7 @@ static DispatchTable instruction_table_extended = {
     [0x61] = z80_inst_out_c_r,
     [0x62] = z80_inst_sbc_hl_ss,
     [0x63] = z80_inst_ld_inn_dd,
-    [0x64] = z80_inst_unimplemented,  // TODO
+    [0x64] = z80_inst_neg,
     [0x65] = z80_inst_retn,
     [0x66] = z80_inst_im,
     [0x67] = z80_inst_unimplemented,  // TODO
@@ -369,7 +369,7 @@ static DispatchTable instruction_table_extended = {
     [0x69] = z80_inst_out_c_r,
     [0x6A] = z80_inst_adc_hl_ss,
     [0x6B] = z80_inst_ld_dd_inn,
-    [0x6C] = z80_inst_unimplemented,  // TODO
+    [0x6C] = z80_inst_neg,
     [0x6D] = z80_inst_retn,
     [0x6E] = z80_inst_im,
     [0x6F] = z80_inst_unimplemented,  // TODO
@@ -377,7 +377,7 @@ static DispatchTable instruction_table_extended = {
     [0x71] = z80_inst_out_c_r,
     [0x72] = z80_inst_sbc_hl_ss,
     [0x73] = z80_inst_ld_inn_dd,
-    [0x74] = z80_inst_unimplemented,  // TODO
+    [0x74] = z80_inst_neg,
     [0x75] = z80_inst_retn,
     [0x76] = z80_inst_im,
     [0x77] = z80_inst_nop2,
@@ -385,7 +385,7 @@ static DispatchTable instruction_table_extended = {
     [0x79] = z80_inst_out_c_r,
     [0x7A] = z80_inst_adc_hl_ss,
     [0x7B] = z80_inst_ld_dd_inn,
-    [0x7C] = z80_inst_unimplemented,  // TODO
+    [0x7C] = z80_inst_neg,
     [0x7D] = z80_inst_retn,
     [0x7E] = z80_inst_im,
     [0x7F] = z80_inst_nop2,