diff --git a/include/mos6502.h b/include/mos6502.h
index 66805bb..9f097cf 100644
--- a/include/mos6502.h
+++ b/include/mos6502.h
@@ -82,7 +82,8 @@ extern void mos6502_free(mos6502 *);
 extern vm_8bit mos6502_next_byte(mos6502 *);
 extern void mos6502_push_stack(mos6502 *, vm_16bit);
 extern vm_16bit mos6502_pop_stack(mos6502 *);
-extern void mos6502_modify_status(mos6502 *, int, vm_8bit);
+extern void mos6502_set_status(mos6502 *, vm_8bit);
+extern void mos6502_modify_status(mos6502 *, vm_8bit, vm_8bit);
 
 extern mos6502_address_resolver mos6502_get_address_resolver(int);
 
diff --git a/src/mos6502.arith.c b/src/mos6502.arith.c
index 83693a7..72744d7 100644
--- a/src/mos6502.arith.c
+++ b/src/mos6502.arith.c
@@ -63,5 +63,5 @@ DEFINE_INST(iny)
 DEFINE_INST(sbc)
 {
     CARRY_BIT();
-    cpu->A -= oper - carry;
+    cpu->A = cpu->A - oper - carry;
 }
diff --git a/src/mos6502.bits.c b/src/mos6502.bits.c
index 8f9fbce..a81f5e0 100644
--- a/src/mos6502.bits.c
+++ b/src/mos6502.bits.c
@@ -12,12 +12,13 @@ DEFINE_INST(and)
 
 DEFINE_INST(asl)
 {
-    oper <<= 1;
-
+    cpu->P &= ~CARRY;
     if (oper & 0x80) {
         cpu->P |= CARRY;
     }
 
+    oper <<= 1;
+
     if (cpu->last_addr) {
         vm_segment_set(cpu->memory, cpu->last_addr, oper);
     } else {
@@ -27,18 +28,20 @@ DEFINE_INST(asl)
 
 DEFINE_INST(bit)
 {
+    cpu->P &= ~NEGATIVE;
     if (oper & NEGATIVE) {
         cpu->P |= NEGATIVE;
     }
 
+    cpu->P &= ~OVERFLOW;
     if (oper & OVERFLOW) {
         cpu->P |= OVERFLOW;
     }
 
     if (oper & cpu->A) {
-        cpu->P |= ZERO;
-    } else {
         cpu->P &= ~ZERO;
+    } else {
+        cpu->P |= ZERO;
     }
 }
 
@@ -49,12 +52,13 @@ DEFINE_INST(eor)
 
 DEFINE_INST(lsr)
 {
-    oper >>= 1;
-
+    cpu->P &= ~CARRY;
     if (oper & 0x01) {
         cpu->P |= CARRY;
     }
 
+    oper >>= 1;
+
     if (cpu->last_addr) {
         vm_segment_set(cpu->memory, cpu->last_addr, oper);
     } else {
diff --git a/src/mos6502.c b/src/mos6502.c
index c6b06c7..d945afc 100644
--- a/src/mos6502.c
+++ b/src/mos6502.c
@@ -133,48 +133,39 @@ mos6502_pop_stack(mos6502 *cpu)
 }
 
 void
-mos6502_modify_status(mos6502 *cpu, int statuses, vm_8bit oper)
+mos6502_set_status(mos6502 *cpu, vm_8bit status)
 {
-    if (statuses & NEGATIVE) {
+    cpu->P = status;
+}
+
+void
+mos6502_modify_status(mos6502 *cpu, vm_8bit status, vm_8bit oper)
+{
+    if (status & NEGATIVE) {
         cpu->P &= ~NEGATIVE;
         if (oper & 0x80) {
             cpu->P |= NEGATIVE;
         }
     }
 
-    if (statuses & OVERFLOW) {
+    if (status & OVERFLOW) {
         cpu->P &= ~OVERFLOW;
         if (oper & OVERFLOW) {
             cpu->P |= OVERFLOW;
         }
     }
 
-    // We're kind of dumb about break, decimal and interrupt. I'm
-    // probably lacking some knowledge about how these work...
-    if (statuses & BREAK) {
-        cpu->P |= BREAK;
-    }
-
-    if (statuses & DECIMAL) {
-        cpu->P |= DECIMAL;
-    }
-
-    if (statuses & INTERRUPT) {
-        cpu->P |= INTERRUPT;
-    }
-
-    if (statuses & CARRY) {
+    if (status & CARRY) {
         cpu->P &= ~CARRY;
         if (oper > 0) {
             cpu->P |= CARRY;
         }
     }
 
-    if (statuses & ZERO) {
+    if (status & ZERO) {
         cpu->P &= ~ZERO;
         if (oper == 0) {
             cpu->P |= ZERO;
         }
     }
-
 }
diff --git a/tests/mos6502.arith.c b/tests/mos6502.arith.c
new file mode 100644
index 0000000..931d5f7
--- /dev/null
+++ b/tests/mos6502.arith.c
@@ -0,0 +1,163 @@
+#include <criterion/criterion.h>
+
+#include "mos6502.h"
+#include "mos6502.enums.h"
+
+Test(mos6502, adc)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_adc(cpu, 3);
+    cr_assert_eq(cpu->A, 8);
+
+    cpu->P |= CARRY;
+    mos6502_handle_adc(cpu, 64);
+    cr_assert_eq(cpu->A, 73);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, cmp)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_cmp(cpu, 3);
+    cr_assert_eq(cpu->P & CARRY, CARRY);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    cpu->A = 3;
+    mos6502_handle_cmp(cpu, 3);
+    cr_assert_eq(cpu->P & CARRY, 0);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & ZERO, ZERO);
+
+    cpu->A = 192;
+    mos6502_handle_cmp(cpu, 3);
+    cr_assert_eq(cpu->P & CARRY, CARRY);
+    cr_assert_eq(cpu->P & NEGATIVE, NEGATIVE);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, cpx)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->X = 5;
+    mos6502_handle_cpx(cpu, 3);
+    cr_assert_eq(cpu->P & CARRY, CARRY);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, cpy)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->Y = 5;
+    mos6502_handle_cpy(cpu, 3);
+    cr_assert_eq(cpu->P & CARRY, CARRY);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, dec)
+{
+    START_CPU_TEST(mos6502);
+
+    // Note that DEC does NOT decrement the accumulator if the last
+    // address is not set. It does _nothing_.
+    cpu->A = 5;
+    mos6502_handle_dec(cpu, 0);
+    cr_assert_neq(cpu->A, 4);
+
+    cpu->last_addr = 123;
+    vm_segment_set(cpu->memory, 123, 44);
+
+    // Note _also_ that DEC expects the number to be decremented will be
+    // passed in as the effective operand, although it doesn't
+    // necessarily need for that to be so.
+    mos6502_handle_dec(cpu, 44);
+    cr_assert_eq(vm_segment_get(cpu->memory, 123), 43);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, dex)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->X = 5;
+    mos6502_handle_dex(cpu, 0);
+    cr_assert_eq(cpu->X, 4);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, dey)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->Y = 5;
+    mos6502_handle_dey(cpu, 0);
+    cr_assert_eq(cpu->Y, 4);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, inc)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_inc(cpu, 55);
+    cr_assert_eq(vm_segment_get(cpu->memory, 123), 56);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, inx)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->X = 5;
+    mos6502_handle_inx(cpu, 0);
+    cr_assert_eq(cpu->X, 6);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, iny)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->Y = 5;
+    mos6502_handle_iny(cpu, 0);
+    cr_assert_eq(cpu->Y, 6);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, sbc)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_sbc(cpu, 3);
+    cr_assert_eq(cpu->A, 2);
+
+    cpu->P |= CARRY;
+    cpu->A = 16;
+    mos6502_handle_sbc(cpu, 8);
+    cr_assert_eq(cpu->A, 7);
+
+    END_CPU_TEST(mos6502);
+}
diff --git a/tests/mos6502.bits.c b/tests/mos6502.bits.c
new file mode 100644
index 0000000..666f2fd
--- /dev/null
+++ b/tests/mos6502.bits.c
@@ -0,0 +1,140 @@
+#include <criterion/criterion.h>
+
+#include "mos6502.h"
+#include "mos6502.enums.h"
+
+Test(mos6502, and)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_and(cpu, 1);
+    cr_assert_eq(cpu->A, 1);
+
+    cpu->A = 5;
+    mos6502_handle_and(cpu, 4);
+    cr_assert_eq(cpu->A, 4);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, asl)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_asl(cpu, 5);
+    cr_assert_eq(cpu->A, 10);
+
+    cpu->last_addr = 123;
+    mos6502_handle_asl(cpu, 22);
+    cr_assert_eq(vm_segment_get(cpu->memory, 123), 44);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bit)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_bit(cpu, 129);
+    cr_assert_eq(cpu->P & NEGATIVE, NEGATIVE);
+    cr_assert_eq(cpu->P & OVERFLOW, 0);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    mos6502_handle_bit(cpu, 193);
+    cr_assert_eq(cpu->P & NEGATIVE, NEGATIVE);
+    cr_assert_eq(cpu->P & OVERFLOW, OVERFLOW);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    mos6502_handle_bit(cpu, 65);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & OVERFLOW, OVERFLOW);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    mos6502_handle_bit(cpu, 33);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & OVERFLOW, 0);
+    cr_assert_eq(cpu->P & ZERO, 0);
+
+    mos6502_handle_bit(cpu, 0);
+    cr_assert_eq(cpu->P & NEGATIVE, 0);
+    cr_assert_eq(cpu->P & OVERFLOW, 0);
+    cr_assert_eq(cpu->P & ZERO, ZERO);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, eor)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_eor(cpu, 4);
+    cr_assert_eq(cpu->A, 1);
+
+    cpu->A = 5;
+    mos6502_handle_eor(cpu, 1);
+    cr_assert_eq(cpu->A, 4);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, lsr)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_lsr(cpu, 5);
+    cr_assert_eq(cpu->A, 2);
+    cr_assert_eq(cpu->P & CARRY, CARRY);
+
+    cpu->last_addr = 123;
+    mos6502_handle_lsr(cpu, 22);
+    cr_assert_eq(vm_segment_get(cpu->memory, 123), 11);
+    cr_assert_eq(cpu->P & CARRY, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, ora)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 5;
+    mos6502_handle_ora(cpu, 4);
+    cr_assert_eq(cpu->A, 5);
+
+    cpu->A = 5;
+    mos6502_handle_ora(cpu, 10);
+    cr_assert_eq(cpu->A, 15);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, rol)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_rol(cpu, 8);
+    cr_assert_eq(cpu->A, 16);
+
+    cpu->last_addr = 234;
+    mos6502_handle_rol(cpu, 128);
+    cr_assert_eq(vm_segment_get(cpu->memory, 234), 1);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, ror)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_ror(cpu, 64);
+    cr_assert_eq(cpu->A, 32);
+
+    cpu->last_addr = 123;
+    mos6502_handle_ror(cpu, 1);
+    cr_assert_eq(vm_segment_get(cpu->memory, 123), 128);
+
+    END_CPU_TEST(mos6502);
+}
diff --git a/tests/mos6502.branch.c b/tests/mos6502.branch.c
new file mode 100644
index 0000000..e3f7ed1
--- /dev/null
+++ b/tests/mos6502.branch.c
@@ -0,0 +1,132 @@
+#include <criterion/criterion.h>
+
+#include "mos6502.h"
+#include "mos6502.enums.h"
+
+Test(mos6502, bcc)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bcc(cpu, 0);
+    cr_assert_eq(cpu->PC, 123);
+
+    cpu->P |= CARRY;
+    cpu->last_addr = 125;
+    mos6502_handle_bcc(cpu, 0);
+    cr_assert_neq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bcs)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bcs(cpu, 0);
+    cr_assert_neq(cpu->PC, 123);
+
+    cpu->P |= CARRY;
+    cpu->last_addr = 125;
+    mos6502_handle_bcs(cpu, 0);
+    cr_assert_eq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, beq)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_beq(cpu, 0);
+    cr_assert_neq(cpu->PC, 123);
+
+    cpu->P |= ZERO;
+    cpu->last_addr = 125;
+    mos6502_handle_beq(cpu, 0);
+    cr_assert_eq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bmi)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bmi(cpu, 0);
+    cr_assert_neq(cpu->PC, 123);
+
+    cpu->P |= NEGATIVE;
+    cpu->last_addr = 125;
+    mos6502_handle_bmi(cpu, 0);
+    cr_assert_eq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bne)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bne(cpu, 0);
+    cr_assert_eq(cpu->PC, 123);
+
+    cpu->P |= ZERO;
+    cpu->last_addr = 125;
+    mos6502_handle_bne(cpu, 0);
+    cr_assert_neq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bpl)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bpl(cpu, 0);
+    cr_assert_eq(cpu->PC, 123);
+
+    cpu->P |= NEGATIVE;
+    cpu->last_addr = 125;
+    mos6502_handle_bpl(cpu, 0);
+    cr_assert_neq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bvc)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bvc(cpu, 0);
+    cr_assert_eq(cpu->PC, 123);
+
+    cpu->P |= OVERFLOW;
+    cpu->last_addr = 125;
+    mos6502_handle_bvc(cpu, 0);
+    cr_assert_neq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, bvs)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->last_addr = 123;
+    mos6502_handle_bvs(cpu, 0);
+    cr_assert_neq(cpu->PC, 123);
+
+    cpu->P |= OVERFLOW;
+    cpu->last_addr = 125;
+    mos6502_handle_bvs(cpu, 0);
+    cr_assert_eq(cpu->PC, 125);
+
+    END_CPU_TEST(mos6502);
+}
diff --git a/tests/mos6502.c b/tests/mos6502.c
index 3454249..4d24b17 100644
--- a/tests/mos6502.c
+++ b/tests/mos6502.c
@@ -71,11 +71,6 @@ Test(mos6502, modify_status)
     mos6502_modify_status(cpu, OVERFLOW, 44);
     cr_assert_neq(cpu->P & OVERFLOW, OVERFLOW);
 
-    mos6502_modify_status(cpu, BREAK, 0);
-    mos6502_modify_status(cpu, INTERRUPT, 0);
-    mos6502_modify_status(cpu, DECIMAL, 0);
-    cr_assert_eq(cpu->P & BREAK & INTERRUPT & DECIMAL, BREAK & INTERRUPT & DECIMAL);
-
     mos6502_modify_status(cpu, CARRY, 23);
     cr_assert_eq(cpu->P & CARRY, CARRY);
     mos6502_modify_status(cpu, CARRY, 0);
@@ -88,3 +83,13 @@ Test(mos6502, modify_status)
 
     END_CPU_TEST(mos6502);
 }
+
+Test(mos6502, set_status)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_set_status(cpu, BREAK | INTERRUPT | DECIMAL);
+    cr_assert_eq(cpu->P & (BREAK | INTERRUPT | DECIMAL), BREAK | INTERRUPT | DECIMAL);
+
+    END_CPU_TEST(mos6502);
+}
diff --git a/tests/mos6502.exec.c b/tests/mos6502.exec.c
new file mode 100644
index 0000000..e2954f1
--- /dev/null
+++ b/tests/mos6502.exec.c
@@ -0,0 +1,74 @@
+#include <criterion/criterion.h>
+
+#include "mos6502.h"
+#include "mos6502.enums.h"
+
+Test(mos6502, brk)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->PC = 123;
+    mos6502_handle_brk(cpu, 0);
+    cr_assert_eq(cpu->PC, 125);
+    cr_assert_eq(cpu->P & INTERRUPT, INTERRUPT);
+    cr_assert_eq(mos6502_pop_stack(cpu), 123);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, jmp)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->PC = 123;
+    cpu->last_addr = 234;
+    mos6502_handle_jmp(cpu, 0);
+
+    cr_assert_eq(cpu->PC, 234);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, jsr)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->PC = 123;
+    cpu->last_addr = 235;
+    mos6502_handle_jsr(cpu, 0);
+
+    cr_assert_eq(cpu->PC, 235);
+    cr_assert_eq(mos6502_pop_stack(cpu), 125);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, nop)
+{
+    // currently this test does nothing -- we _should_ test to see if we
+    // pass the right number of cycles, though.
+}
+
+Test(mos6502, rti)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_push_stack(cpu, 222);
+    mos6502_handle_rti(cpu, 0);
+
+    cr_assert_eq(cpu->PC, 222);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, rts)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_push_stack(cpu, 333);
+    mos6502_handle_rti(cpu, 0);
+
+    cr_assert_eq(cpu->PC, 333);
+
+    END_CPU_TEST(mos6502);
+}
diff --git a/tests/mos6502.loadstor.c b/tests/mos6502.loadstor.c
index d6e062a..ae45054 100644
--- a/tests/mos6502.loadstor.c
+++ b/tests/mos6502.loadstor.c
@@ -2,3 +2,191 @@
 
 #include "mos6502.h"
 #include "mos6502.enums.h"
+
+Test(mos6502, lda)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_lda(cpu, 123);
+    cr_assert_eq(cpu->A, 123);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, ldx)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_ldx(cpu, 123);
+    cr_assert_eq(cpu->X, 123);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, ldy)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_handle_ldy(cpu, 123);
+    cr_assert_eq(cpu->Y, 123);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, pha)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 0x24;
+    mos6502_handle_pha(cpu, 0);
+
+    cr_assert_eq(vm_segment_get(cpu->memory, 0x0100), 0x00);
+    cr_assert_eq(vm_segment_get(cpu->memory, 0x0101), 0x24);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, php)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = 0x43;
+    mos6502_handle_php(cpu, 0);
+
+    cr_assert_eq(vm_segment_get(cpu->memory, 0x0100), 0x00);
+    cr_assert_eq(vm_segment_get(cpu->memory, 0x0101), 0x43);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, pla)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_push_stack(cpu, 0x0033);
+    mos6502_handle_pla(cpu, 0);
+
+    cr_assert_eq(cpu->A, 0x33);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, plp)
+{
+    START_CPU_TEST(mos6502);
+
+    mos6502_push_stack(cpu, 0x0052);
+    mos6502_handle_plp(cpu, 0);
+
+    cr_assert_eq(cpu->P, 0x52);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, sta)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 123;
+    cpu->last_addr = 555;
+    mos6502_handle_sta(cpu, 0);
+    cr_assert_eq(vm_segment_get(cpu->memory, cpu->last_addr), cpu->A);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, stx)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->X = 222;
+    cpu->last_addr = 444;
+    mos6502_handle_stx(cpu, 0);
+    cr_assert_eq(vm_segment_get(cpu->memory, cpu->last_addr), cpu->X);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, sty)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->Y = 111;
+    cpu->last_addr = 253;
+    mos6502_handle_sty(cpu, 0);
+    cr_assert_eq(vm_segment_get(cpu->memory, cpu->last_addr), cpu->Y);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, tax)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 111;
+    cpu->X = 222;
+    mos6502_handle_tax(cpu, 0);
+    cr_assert_eq(cpu->X, 111);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, tay)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 111;
+    cpu->Y = 115;
+    mos6502_handle_tay(cpu, 0);
+    cr_assert_eq(cpu->Y, 111);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, tsx)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->S = 111;
+    cpu->X = 222;
+    mos6502_handle_tsx(cpu, 0);
+    cr_assert_eq(cpu->X, 111);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, txa)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 111;
+    cpu->X = 222;
+    mos6502_handle_txa(cpu, 0);
+    cr_assert_eq(cpu->A, 222);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, txs)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->S = 111;
+    cpu->X = 222;
+    mos6502_handle_txs(cpu, 0);
+    cr_assert_eq(cpu->S, 222);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, tya)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->A = 111;
+    cpu->Y = 222;
+    mos6502_handle_tya(cpu, 0);
+    cr_assert_eq(cpu->A, 222);
+
+    END_CPU_TEST(mos6502);
+}
diff --git a/tests/mos6502.stat.c b/tests/mos6502.stat.c
new file mode 100644
index 0000000..47d0de8
--- /dev/null
+++ b/tests/mos6502.stat.c
@@ -0,0 +1,82 @@
+#include <criterion/criterion.h>
+
+#include "mos6502.h"
+#include "mos6502.enums.h"
+
+Test(mos6502, clc)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = CARRY | DECIMAL;
+    mos6502_handle_clc(cpu, 0);
+    cr_assert_eq(cpu->P & CARRY, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, cld)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = DECIMAL | CARRY;
+    mos6502_handle_cld(cpu, 0);
+    cr_assert_eq(cpu->P & DECIMAL, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, cli)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = CARRY | INTERRUPT;
+    mos6502_handle_cli(cpu, 0);
+    cr_assert_eq(cpu->P & INTERRUPT, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, clv)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = CARRY | OVERFLOW;
+    mos6502_handle_clv(cpu, 0);
+    cr_assert_eq(cpu->P & OVERFLOW, 0);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, sec)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = 0;
+    mos6502_handle_sec(cpu, 0);
+    cr_assert_eq(cpu->P & CARRY, CARRY);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, sed)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = 0;
+    mos6502_handle_sed(cpu, 0);
+    cr_assert_eq(cpu->P & DECIMAL, DECIMAL);
+
+    END_CPU_TEST(mos6502);
+}
+
+Test(mos6502, sei)
+{
+    START_CPU_TEST(mos6502);
+
+    cpu->P = 0;
+    mos6502_handle_sei(cpu, 0);
+    cr_assert_eq(cpu->P & INTERRUPT, INTERRUPT);
+
+    END_CPU_TEST(mos6502);
+}
+