4049

Instead of organizing layers by instruction, do so by addressing mode.

3 files changed, 101 insertions, 99 deletions

diff --git a/subx/011add.cc b/subx/011indirect_addressing.cc
index 2f3c83ac..8800727e 100644
--- a/subx/011add.cc
+++ b/subx/011indirect_addressing.cc
@@ -1,4 +1,4 @@
-//:: register indirect addressing
+//: operating on memory at the address provided by some register
 
 :(scenario add_r32_to_mem_at_r32)
 % Reg[3].i = 0x10;
@@ -50,56 +50,6 @@ int32_t* effective_address(uint8_t modrm) {
   return result;
 }
 
-//:: register direct addressing
-
-:(scenario add_imm32_to_r32)
-% Reg[3].i = 1;
-# op  ModRM   SIB   displacement  immediate
-  81  c3                          0a 0b 0c 0d  # add 0x0d0c0b0a to EBX (reg 3)
-+run: combine imm32 0x0d0c0b0a with effective address
-+run: effective address is reg 3
-+run: subop add
-+run: storing 0x0d0c0b0b
-
-:(before "End Single-Byte Opcodes")
-case 0x81: {  // combine imm32 with r/m32
-  uint8_t modrm = next();
-  int32_t arg2 = imm32();
-  trace(2, "run") << "combine imm32 0x" << HEXWORD << arg2 << " with effective address" << end();
-  int32_t* arg1 = effective_address(modrm);
-  uint8_t subop = (modrm>>3)&0x7;  // middle 3 'reg opcode' bits
-  switch (subop) {
-  case 0:
-    trace(2, "run") << "subop add" << end();
-    BINARY_ARITHMETIC_OP(+, *arg1, arg2);
-    break;
-  // End Op 81 Subops
-  default:
-    cerr << "unrecognized sub-opcode after 81: " << NUM(subop) << '\n';
-    exit(1);
-  }
-  break;
-}
-
-:(before "End Mod Special-cases")
-case 3:
-  // mod 3 is just register direct addressing
-  trace(2, "run") << "effective address is reg " << NUM(rm) << end();
-  result = &Reg[rm].i;
-  break;
-
-//:: lots more tests
-
-:(scenario add_imm32_to_mem_at_r32)
-% Reg[3].i = 0x60;
-% Mem.at(0x60) = 1;
-# op  ModR/M  SIB   displacement  immediate
-  81  03                          0a 0b 0c 0d  # add 0x0d0c0b0a to *EBX (reg 3)
-+run: combine imm32 0x0d0c0b0a with effective address
-+run: effective address is mem at address 0x60 (reg 3)
-+run: subop add
-+run: storing 0x0d0c0b0b
-
 //:
 
 :(scenario add_mem_at_r32_to_r32)
@@ -122,54 +72,7 @@ case 0x03: {  // add r/m32 to r32
   break;
 }
 
-//:
-
-:(scenario sub_imm32_from_eax)
-% Reg[EAX].i = 0x0d0c0baa;
-# op  ModR/M  SIB   displacement  immediate
-  2d                              0a 0b 0c 0d  # subtract 0x0d0c0b0a from EAX (reg 0)
-+run: subtract imm32 0x0d0c0b0a from reg EAX
-+run: storing 0x000000a0
-
-:(before "End Single-Byte Opcodes")
-case 0x2d: {  // subtract imm32 from EAX
-  int32_t arg2 = imm32();
-  trace(2, "run") << "subtract imm32 0x" << HEXWORD << arg2 << " from reg EAX" << end();
-  BINARY_ARITHMETIC_OP(-, Reg[EAX].i, arg2);
-  break;
-}
-
-//:
-
-:(scenario sub_imm32_from_r32)
-% Reg[3].i = 10;
-# op  ModRM   SIB   displacement  immediate
-  81  eb                          01 00 00 00  # subtract 1 from EBX (reg 3)
-+run: combine imm32 0x00000001 with effective address
-+run: effective address is reg 3
-+run: subop subtract
-+run: storing 0x00000009
-
-:(before "End Op 81 Subops")
-case 5: {
-  trace(2, "run") << "subop subtract" << end();
-  BINARY_ARITHMETIC_OP(-, *arg1, arg2);
-  break;
-}
-
-//:
-
-:(scenario sub_imm32_from_mem_at_r32)
-% Reg[3].i = 0x60;
-% Mem.at(0x60) = 10;
-# op  ModRM   SIB   displacement  immediate
-  81  2b                          01 00 00 00  # subtract 1 from *EBX (reg 3)
-+run: combine imm32 0x00000001 with effective address
-+run: effective address is mem at address 0x60 (reg 3)
-+run: subop subtract
-+run: storing 0x00000009
-
-//:
+//:: subtract
 
 :(scenario sub_r32_from_mem_at_r32)
 % Reg[0].i = 0x60;
diff --git a/subx/012direct_addressing.cc b/subx/012direct_addressing.cc
new file mode 100644
index 00000000..d788904b
--- /dev/null
+++ b/subx/012direct_addressing.cc
@@ -0,0 +1,10 @@
+//: operating directly on a register
+
+:(before "End Mod Special-cases")
+case 3:
+  // mod 3 is just register direct addressing
+  trace(2, "run") << "effective address is reg " << NUM(rm) << end();
+  result = &Reg[rm].i;
+  break;
+
+//:: subtract
diff --git a/subx/013immediate_addressing.cc b/subx/013immediate_addressing.cc
new file mode 100644
index 00000000..25a362c2
--- /dev/null
+++ b/subx/013immediate_addressing.cc
@@ -0,0 +1,89 @@
+//: instructions that (immediately) contain an argument to act with
+
+:(scenario add_imm32_to_r32)
+% Reg[3].i = 1;
+# op  ModRM   SIB   displacement  immediate
+  81  c3                          0a 0b 0c 0d  # add 0x0d0c0b0a to EBX (reg 3)
++run: combine imm32 0x0d0c0b0a with effective address
++run: effective address is reg 3
++run: subop add
++run: storing 0x0d0c0b0b
+
+:(before "End Single-Byte Opcodes")
+case 0x81: {  // combine imm32 with r/m32
+  uint8_t modrm = next();
+  int32_t arg2 = imm32();
+  trace(2, "run") << "combine imm32 0x" << HEXWORD << arg2 << " with effective address" << end();
+  int32_t* arg1 = effective_address(modrm);
+  uint8_t subop = (modrm>>3)&0x7;  // middle 3 'reg opcode' bits
+  switch (subop) {
+  case 0:
+    trace(2, "run") << "subop add" << end();
+    BINARY_ARITHMETIC_OP(+, *arg1, arg2);
+    break;
+  // End Op 81 Subops
+  default:
+    cerr << "unrecognized sub-opcode after 81: " << NUM(subop) << '\n';
+    exit(1);
+  }
+  break;
+}
+
+//:
+
+:(scenario add_imm32_to_mem_at_r32)
+% Reg[3].i = 0x60;
+% Mem.at(0x60) = 1;
+# op  ModR/M  SIB   displacement  immediate
+  81  03                          0a 0b 0c 0d  # add 0x0d0c0b0a to *EBX (reg 3)
++run: combine imm32 0x0d0c0b0a with effective address
++run: effective address is mem at address 0x60 (reg 3)
++run: subop add
++run: storing 0x0d0c0b0b
+
+//:: subtract
+
+:(scenario sub_imm32_from_eax)
+% Reg[EAX].i = 0x0d0c0baa;
+# op  ModR/M  SIB   displacement  immediate
+  2d                              0a 0b 0c 0d  # subtract 0x0d0c0b0a from EAX (reg 0)
++run: subtract imm32 0x0d0c0b0a from reg EAX
++run: storing 0x000000a0
+
+:(before "End Single-Byte Opcodes")
+case 0x2d: {  // subtract imm32 from EAX
+  int32_t arg2 = imm32();
+  trace(2, "run") << "subtract imm32 0x" << HEXWORD << arg2 << " from reg EAX" << end();
+  BINARY_ARITHMETIC_OP(-, Reg[EAX].i, arg2);
+  break;
+}
+
+//:
+
+:(scenario sub_imm32_from_mem_at_r32)
+% Reg[3].i = 0x60;
+% Mem.at(0x60) = 10;
+# op  ModRM   SIB   displacement  immediate
+  81  2b                          01 00 00 00  # subtract 1 from *EBX (reg 3)
++run: combine imm32 0x00000001 with effective address
++run: effective address is mem at address 0x60 (reg 3)
++run: subop subtract
++run: storing 0x00000009
+
+//:
+
+:(scenario sub_imm32_from_r32)
+% Reg[3].i = 10;
+# op  ModRM   SIB   displacement  immediate
+  81  eb                          01 00 00 00  # subtract 1 from EBX (reg 3)
++run: combine imm32 0x00000001 with effective address
++run: effective address is reg 3
++run: subop subtract
++run: storing 0x00000009
+
+:(before "End Op 81 Subops")
+case 5: {
+  trace(2, "run") << "subop subtract" << end();
+  BINARY_ARITHMETIC_OP(-, *arg1, arg2);
+  break;
+}