diff --git a/dos/prn/print.k b/dos/prn/print.k
index b12ddcf..7c5a41e 100644
--- a/dos/prn/print.k
+++ b/dos/prn/print.k
@@ -15,7 +15,7 @@ print:
 
 .1:
     test b[ax0], b[ax0]
-    jz .2
+    cjmpz .2
     prn b[ax0]
     inc ax0
     loop .1
diff --git a/dos/str/strcpy.k b/dos/str/strcpy.k
index 8336202..819031c 100644
--- a/dos/str/strcpy.k
+++ b/dos/str/strcpy.k
@@ -5,6 +5,15 @@
 ; void strcpy(char *, const char *)
 ;
 strcpy:
+    test b[ax1], b[ax1]
+    cmovz b[ax0], 0
+    cretz
+
+.1:
+    test b[ax1], b[ax1]
+    cmovz b[ax0], 0
+    cretz
+
     ret
 
 ;
diff --git a/dos/str/strlen.k b/dos/str/strlen.k
index e8bc4de..9bc9a58 100644
--- a/dos/str/strlen.k
+++ b/dos/str/strlen.k
@@ -9,31 +9,27 @@ strlen:
 
 .1:
     test b[ax0], b[ax0]
-    jz .2
+    cretz
 
     inc rax
     inc ax0
     jmp .1
 
-.2:
-    ret
-
 ;
 ; int strnlen(char *, int)
 ;
 strnlen:
     xor rax, rax
     mov rcx, ax1
-    jcxz .2
+    ;jcxz .2
     dec rcx
 
 .1:
     test b[ax0], b[ax0]
-    jz .2
+    cretz
 
     inc rax
     inc ax0
     loop .1
 
-.2:
     ret
diff --git a/dos/str/strrev.k b/dos/str/strrev.k
index 002afbd..48c24db 100644
--- a/dos/str/strrev.k
+++ b/dos/str/strrev.k
@@ -7,7 +7,7 @@
 strrev:
     test b[ax1], b[ax1]
     cmovz b[ax0], 0
-    jz .4
+    cretz
 
     ; save str's location
     mov rdx, ax1
@@ -16,25 +16,19 @@ strrev:
     ; the null terminator
 .1:
     test b[ax1+1], b[ax1+1]
-    jz .2
-
-    inc ax1
-    jmp .1
+    cincnz ax1
+    cjmpnz .1
 
+.2:
     ; copy, going backward though str
     ; and forward through buf
-.2:
     mov b[ax0], b[ax1]
 
     cmp ax1, rdx
-    je .3
+    cmovz b[ax0+1], 0
+    cretz
 
     inc ax0
     dec ax1
     jmp .2
 
-.3:
-    mov b[ax0+1], 0
-
-.4:
-    ret
diff --git a/pc/Makefile b/pc/Makefile
index 4d1ad7c..1e54f5f 100644
--- a/pc/Makefile
+++ b/pc/Makefile
@@ -12,7 +12,7 @@ obj = $(patsubst %.c,%.o,$(src))
 
 CFLAGS=-O2 -g -Wall -fno-builtin-log
 
-%.o: %.c i_arch.h *.h $(src)
+%.o: %.c i_arch.h *.h */*.h $(src)
 	@gcc $(CFLAGS) -c $< -o $@
 
 i_arch.h: instrs/INSTRS instrs/arch_i.py
diff --git a/pc/instrs/INSTRS b/pc/instrs/INSTRS
index 9a021e9..2ee728f 100644
--- a/pc/instrs/INSTRS
+++ b/pc/instrs/INSTRS
@@ -59,6 +59,20 @@ add m r
 add m i
 add m m
 
+caddz r r
+caddz r i
+caddz r m
+caddz m r
+caddz m i
+caddz m m
+
+caddnz r r
+caddnz r i
+caddnz r m
+caddnz m r
+caddnz m i
+caddnz m m
+
 sub r r
 sub r i
 sub r m
@@ -66,22 +80,60 @@ sub m r
 sub m i
 sub m m
 
+csubz r r
+csubz r i
+csubz r m
+csubz m r
+csubz m i
+csubz m m
+
+csubnz r r
+csubnz r i
+csubnz r m
+csubnz m r
+csubnz m i
+csubnz m m
+
 # rdx = hi(rax * $0)
 # rax = lo(rax * $0)
 mul r
 mul i
 
+cmulz r
+cmulz i
+
+cmulnz r
+cmulnz i
+
 # rdx = rax % $0
 # rax = rax / $0
 div r
 div i
 
+cdivz r
+cdivz i
+
+cdivnz r
+cdivnz i
+
 inc r
 inc m
 
+cincz r
+cincz m
+
+cincnz r
+cincnz m
+
 dec r
 dec m
 
+cdecz r
+cdecz m
+
+cdecnz r
+cdecnz m
+
 #
 # Comparison instruction
 #
@@ -115,30 +167,34 @@ test m m
 jmp r
 jmp i
 
-loop r
-loop i
+cjmpz r
+cjmpz i
+cjmpnz r
+cjmpnz i
 
-jz r
-jz i
-jnz r
-jnz i
-je r
-je i
-jne r
-jne i
+cjmpa r
+cjmpa i
+cjmpae r
+cjmpae i
 
-ja r
-ja i
-jae r
-jae i
-
-jb r
-jb i
-jbe r
-jbe i
+cjmpb r
+cjmpb i
+cjmpbe r
+cjmpbe i
 
 jcxz r
 jcxz i
+jcxnz r
+jcxnz i
+
+loop r
+loop i
+
+cloopz r
+cloopz i
+
+cloopnz r
+cloopnz i
 
 #
 # Movement instructions
@@ -151,16 +207,6 @@ mov m r
 mov m i
 mov m m
 
-xchg r r
-xchg r i
-xchg r m
-xchg m r
-xchg m i
-xchg m m
-
-lea r m
-lea m m
-
 cmovz r r
 cmovz r i
 cmovz r m
@@ -175,6 +221,36 @@ cmovnz m r
 cmovnz m i
 cmovnz m m
 
+xchg r r
+xchg r i
+xchg r m
+xchg m r
+xchg m i
+xchg m m
+
+cxchgz r r
+cxchgz r i
+cxchgz r m
+cxchgz m r
+cxchgz m i
+cxchgz m m
+
+cxchgnz r r
+cxchgnz r i
+cxchgnz r m
+cxchgnz m r
+cxchgnz m i
+cxchgnz m m
+
+lea r m
+lea m m
+
+cleaz r m
+cleaz m m
+
+cleanz r m
+cleanz m m
+
 #
 # Stack manipulation instructions
 #
@@ -191,6 +267,8 @@ call i
 call m
 
 ret
+cretz
+cretnz
 
 # push rbp
 # mov rbp, rsp
@@ -199,6 +277,8 @@ enter
 # mov rbp, [rsp+8]
 # add rsp, 8
 leave
+cleavez
+cleavenz
 
 pushf
 
diff --git a/pc/instrs/arith.c b/pc/instrs/arith.c
index c3d2503..c249253 100644
--- a/pc/instrs/arith.c
+++ b/pc/instrs/arith.c
@@ -4,6 +4,13 @@
 #include "instrs.h"
 #include "arch_i.h"
 
+IMPL_COND(inc);
+IMPL_COND(dec);
+IMPL_COND(add);
+IMPL_COND(sub);
+IMPL_COND(mul);
+IMPL_COND(div);
+
 //
 // Unsigned arithmetic instructions
 //
diff --git a/pc/instrs/debug.c b/pc/instrs/debug.c
index 3283093..71dcd6c 100644
--- a/pc/instrs/debug.c
+++ b/pc/instrs/debug.c
@@ -4,6 +4,8 @@
 #include "instrs.h"
 #include "arch_i.h"
 
+IMPL_COND(break);
+
 IMPL_START_0(break)
 {
     log("\nExecuting BREAK INSTR\n");
diff --git a/pc/instrs/instrs.h b/pc/instrs/instrs.h
index 07dd1e5..cdf8291 100644
--- a/pc/instrs/instrs.h
+++ b/pc/instrs/instrs.h
@@ -5,13 +5,13 @@
 
 #define IMPL_START_0(name)                                                  \
 void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
-{                                                                           \
+{
 
 #define IMPL_START_1(name)                                                  \
 void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
 {                                                                           \
     ulong v1 = (p1->type == A_REG ? ctx->r[p1->val].val : p1->val);         \
-    if (p1->mem) v1 = readmem(ctx, v1 + p1->off, p1->mlen);                 \
+    if (p1->mem) v1 = readmem(ctx, v1 + p1->off, p1->mlen);
 
 #define IMPL_START_2(name)                                                  \
 void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
@@ -19,13 +19,13 @@ void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
     ulong v1 = (p1->type == A_REG ? ctx->r[p1->val].val : p1->val);         \
     ulong v2 = (p2->type == A_REG ? ctx->r[p2->val].val : p2->val);         \
     if (p1->mem) v1 = readmem(ctx, v1 + p1->off, p1->mlen);                 \
-    if (p2->mem) v2 = readmem(ctx, v2 + p2->off, p2->mlen);                 \
+    if (p2->mem) v2 = readmem(ctx, v2 + p2->off, p2->mlen);
 
 #define IMPL_START_3(name)                                                  \
 void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
 {                                                                           \
     ulong v2 = (p2->type == A_REG ? ctx->r[p2->val].val : p2->val);         \
-    if (p2->mem) v2 = readmem(ctx, v2 + p2->off, p2->mlen);                 \
+    if (p2->mem) v2 = readmem(ctx, v2 + p2->off, p2->mlen);
 
 #define IMPL_OUT                                                            \
     assert(p1->type == A_REG || p1->mem);                                   \
@@ -34,11 +34,41 @@ void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
         writemem(ctx, v1, addr + p1->off, p1->mlen);                        \
     }                                                                       \
     else ctx->r[p1->val].val = v1;                                          \
-}                                                                           \
+}
 
 #define IMPL_END                                                            \
 }
 
+//
+// c...z instructions easy implementation
+//
+
+#define IMPL_CxxxZ(name)                                                    \
+IMPL_START_0(c##name##z)                                                    \
+{                                                                           \
+    if (ctx->r[FLG].val & ZF) {                                             \
+        i_##name(ctx, p1, p2);                                              \
+    }                                                                       \
+}                                                                           \
+IMPL_END
+
+#define IMPL_CxxxNZ(name)                                                   \
+IMPL_START_0(c##name##nz)                                                   \
+{                                                                           \
+    if (!(ctx->r[FLG].val & ZF)) {                                          \
+        i_##name(ctx, p1, p2);                                              \
+    }                                                                       \
+}                                                                           \
+IMPL_END
+
+#define IMPL_COND(name)                                                     \
+    IMPL_CxxxZ(name);                                                       \
+    IMPL_CxxxNZ(name)
+
+//
+// Consistency checks
+//
+
 #define CHK_SUPERV()                                                        \
     do {                                                                    \
         if ((ctx->r[CR0].val & UF) == 1) {                                  \
@@ -54,9 +84,14 @@ void i_##name(ctx_t *ctx, acc_t *p1, acc_t *p2)                             \
         _except(ctx, E_STK, "RSP above RBP");                               \
     }
 
+
+//
+// Common operations
+//
+
 #define PUSH(v)                                                             \
     writemem64(ctx, v, ctx->r[RSP].val);                                    \
-    ctx->r[RSP].val -= 8;                                                   \
+    ctx->r[RSP].val -= 8;
 
 #define POP(v)                                                              \
     ctx->r[RSP].val += 8;                                                   \
diff --git a/pc/instrs/jumps.c b/pc/instrs/jumps.c
index 4fbf6fe..b74e11b 100644
--- a/pc/instrs/jumps.c
+++ b/pc/instrs/jumps.c
@@ -4,6 +4,9 @@
 #include "instrs.h"
 #include "arch_i.h"
 
+IMPL_COND(jmp);
+IMPL_COND(loop);
+
 //
 // Jump instructions
 //
@@ -23,56 +26,28 @@ IMPL_START_1(loop)
 }
 IMPL_END;
 
-IMPL_START_1(jz)
-{
-    if (ctx->r[FLG].val & ZF)
-        JUMP(v1);
-}
-IMPL_END;
-
-IMPL_START_1(jnz)
-{
-    if (!(ctx->r[FLG].val & ZF))
-        JUMP(v1);
-}
-IMPL_END;
-
-IMPL_START_1(je)
-{
-    if (ctx->r[FLG].val & ZF)
-        JUMP(v1);
-}
-IMPL_END;
-
-IMPL_START_1(jne)
-{
-    if (!(ctx->r[FLG].val & ZF))
-        JUMP(v1);
-}
-IMPL_END;
-
-IMPL_START_1(ja)
+IMPL_START_1(cjmpa)
 {
     if (!(ctx->r[FLG].val & ZF) && !(ctx->r[FLG].val & CF))
         JUMP(v1);
 }
 IMPL_END;
 
-IMPL_START_1(jae)
+IMPL_START_1(cjmpae)
 {
     if (!(ctx->r[FLG].val & CF))
         JUMP(v1);
 }
 IMPL_END;
 
-IMPL_START_1(jb)
+IMPL_START_1(cjmpb)
 {
     if (!(ctx->r[FLG].val & ZF) && ctx->r[FLG].val & CF)
         JUMP(v1);
 }
 IMPL_END;
 
-IMPL_START_1(jbe)
+IMPL_START_1(cjmpbe)
 {
     if (ctx->r[FLG].val & CF)
         JUMP(v1);
@@ -85,3 +60,11 @@ IMPL_START_1(jcxz)
         JUMP(v1);
 }
 IMPL_END;
+
+IMPL_START_1(jcxnz)
+{
+    if (ctx->r[RCX].val)
+        JUMP(v1);
+}
+IMPL_END;
+
diff --git a/pc/instrs/mov.c b/pc/instrs/mov.c
index 87ecd68..ca6bd30 100644
--- a/pc/instrs/mov.c
+++ b/pc/instrs/mov.c
@@ -4,6 +4,10 @@
 #include "instrs.h"
 #include "arch_i.h"
 
+IMPL_COND(mov);
+IMPL_COND(lea);
+IMPL_COND(xchg);
+
 //
 // Movement instructions
 //
@@ -38,17 +42,3 @@ IMPL_START_1(gcs)
 }
 IMPL_OUT;
 
-IMPL_START_2(cmovz)
-{
-    if (ctx->r[FLG].val & ZF)
-        v1 = v2;
-}
-IMPL_OUT;
-
-IMPL_START_2(cmovnz)
-{
-    if (!(ctx->r[FLG].val & ZF))
-        v1 = v2;
-}
-IMPL_OUT;
-
diff --git a/pc/instrs/stack.c b/pc/instrs/stack.c
index cf96805..245c42a 100644
--- a/pc/instrs/stack.c
+++ b/pc/instrs/stack.c
@@ -4,6 +4,9 @@
 #include "instrs.h"
 #include "arch_i.h"
 
+IMPL_COND(ret);
+IMPL_COND(leave);
+
 //
 // Stack manipulation instructions
 //