diff --git a/amach.awk b/amach.awk
index 02ecbd9..fe86f8d 100644
--- a/amach.awk
+++ b/amach.awk
@@ -281,24 +281,24 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
   f3 = int(instr / 8192) % 8
   b12 = int(instr / 4096) % 2
   r11_7 = int(instr / 128) % 32
-  r9_7 = (int(instr / 128) % 8) + 8
+  r9_7 = (r11_7 % 8) + 8
   r6_2 = int(instr / 4) % 32
-  r4_2 = (int(instr / 4) % 8) + 8
+  r4_2 = (r6_2 % 8) + 8
   shamt = r6_2 + b12 * 32
 
   if (op == 0) {
     if (f3 == 0) { # C.ADDI4SPN
-      imm = (int(instr / 128) % 16) * 64 + (int(instr / 2048) % 4) * 16 + (int(instr / 32) % 2) * 8 + (int(instr / 64) % 2) * 4
+      imm = (r11_7 % 16) * 64 + (int(r11_7 / 16) + b12 * 2) * 16 + (int(r6_2 / 8) % 2) * 8 + (int(r6_2 / 16) % 2) * 4
       if (imm == 0) trapout(sprintf("Illegal instruction C.ADDI4SPN at 0x%X", pc-2))
       setreg(r4_2, getreg(2) + imm)
     } else if (f3 == 2) { # C.LW
-      imm = (int(instr / 32) % 2) * 64 + (int(instr / 1024) % 8) * 8 + (int(instr / 64) % 2) * 4
+      imm = (int(r6_2 / 8) % 2) * 64 + (int(r11_7 / 8) % 4) * 8 + b12 * 32 + (int(r6_2 / 16) % 2) * 4
       base = (getreg(r9_7) + imm) % 4294967296
       if (base < 0) base += 4294967296
       val = MEM[base] + MEM[(base+1)%4294967296]*256 + MEM[(base+2)%4294967296]*65536 + MEM[(base+3)%4294967296]*16777216
       setreg(r4_2, val)
     } else if (f3 == 6) { # C.SW
-      imm = (int(instr / 32) % 2) * 64 + (int(instr / 1024) % 8) * 8 + (int(instr / 64) % 2) * 4
+      imm = (int(r6_2 / 8) % 2) * 64 + (int(r11_7 / 8) % 4) * 8 + b12 * 32 + (int(r6_2 / 16) % 2) * 4
       base = (getreg(r9_7) + imm) % 4294967296
       if (base < 0) base += 4294967296
       val = getreg(r4_2)
@@ -314,7 +314,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
       if (imm >= 32) imm -= 64
       setreg(r11_7, getreg(r11_7) + imm)
     } else if (f3 == 1 || f3 == 5) { # C.JAL / C.J
-      imm = b12 * 2048 + (int(instr / 256) % 2) * 1024 + (int(instr / 512) % 4) * 256 + (int(instr / 64) % 2) * 128 + (int(instr / 128) % 2) * 64 + (int(instr / 4) % 2) * 32 + (int(instr / 2048) % 2) * 16 + (int(instr / 8) % 8) * 2
+      imm = b12 * 2048 + (int(r11_7 / 2) % 2) * 1024 + (int(r11_7 / 4) % 4) * 256 + (int(r6_2 / 16) % 2) * 128 + (r11_7 % 2) * 64 + (r6_2 % 2) * 32 + (int(r11_7 / 16)) * 16 + (int(r6_2 / 2) % 8) * 2
       if (imm >= 2048) imm -= 4096
       if (f3 == 1) setreg(1, pc)
       pc = (pc - 2) + imm
@@ -324,7 +324,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
       setreg(r11_7, imm)
     } else if (f3 == 3) { # C.ADDI16SP / C.LUI
       if (r11_7 == 2) { # C.ADDI16SP
-        imm = b12 * 512 + (int(instr / 8) % 4) * 128 + (int(instr / 32) % 2) * 64 + (int(instr / 4) % 2) * 32 + (int(instr / 64) % 2) * 16
+        imm = b12 * 512 + (int(r6_2 / 2) % 4) * 128 + (int(r6_2 / 8) % 2) * 64 + (r6_2 % 2) * 32 + (int(r6_2 / 16) % 2) * 16
         if (imm >= 512) imm -= 1024
         if (imm == 0) trapout(sprintf("Illegal instruction C.ADDI16SP at 0x%X", pc-2))
         setreg(2, getreg(2) + imm)
@@ -336,7 +336,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
         setreg(r11_7, imm)
       }
     } else if (f3 == 4) {
-      val = int(instr / 1024) % 4
+      val = int(r11_7 / 8) % 4
       if (val == 0) { # C.SRLI
         if (shamt >= 32) trapout(sprintf("Illegal shift amount %d at 0x%X", shamt, pc-2))
         imm = getreg(r9_7)
@@ -350,7 +350,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
         if (imm >= 32) imm -= 64
         setreg(r9_7, bw_and(getreg(r9_7), imm))
       } else if (val == 3) { # C.SUB, C.XOR, C.OR, C.AND
-        imm = int(instr / 32) % 4
+        imm = int(r6_2 / 8) % 4
         if (b12 != 0) trapout(sprintf("Illegal register-register instruction at 0x%X", pc-2))
         if (imm == 0) setreg(r9_7, getreg(r9_7) - getreg(r4_2))
         else if (imm == 1) setreg(r9_7, bw_xor(getreg(r9_7), getreg(r4_2)))
@@ -358,7 +358,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
         else if (imm == 3) setreg(r9_7, bw_and(getreg(r9_7), getreg(r4_2)))
       }
     } else if (f3 == 6 || f3 == 7) { # C.BEQZ / C.BNEZ
-      imm = b12 * 256 + (int(instr / 32) % 4) * 64 + (int(instr / 4) % 2) * 32 + (int(instr / 1024) % 4) * 8 + (int(instr / 8) % 4) * 2
+      imm = b12 * 256 + (int(r6_2 / 8) % 4) * 64 + (r6_2 % 2) * 32 + (int(r11_7 / 8) % 4) * 8 + (int(r6_2 / 2) % 4) * 2
       if (imm >= 256) imm -= 512
       val = (f3 == 6) ? (getreg(r9_7) == 0) : (getreg(r9_7) != 0)
       pc = val ? (pc - 2) + imm : pc
@@ -371,7 +371,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
       }
     } else if (f3 == 2) { # C.LWSP
       if (r11_7 == 0) trapout(sprintf("Illegal instruction C.LWSP with rd=0 at 0x%X", pc-2))
-      imm = (int(instr / 4) % 4) * 64 + b12 * 32 + (int(instr / 16) % 8) * 4
+      imm = (r6_2 % 4) * 64 + b12 * 32 + (int(r6_2 / 4) % 8) * 4
       base = (getreg(2) + imm) % 4294967296
       if (base < 0) base += 4294967296
       val = MEM[base] + MEM[(base+1)%4294967296]*256 + MEM[(base+2)%4294967296]*65536 + MEM[(base+3)%4294967296]*16777216
@@ -398,7 +398,7 @@ function amach_comp(instr,  op, f3, b12, r11_7, r9_7, r6_2, r4_2, shamt, imm, ba
         }
       }
     } else if (f3 == 6) { # C.SWSP
-      imm = (int(instr / 128) % 4) * 64 + (int(instr / 512) % 16) * 4
+      imm = (r11_7 % 4) * 64 + int(r11_7 / 4) * 4 + b12 * 32
       base = (getreg(2) + imm) % 4294967296
       if (base < 0) base += 4294967296
       val = getreg(r6_2)