diff options
| -rw-r--r-- | subx/011indirect_addressing.cc (renamed from subx/011add.cc) | 101 | ||||
| -rw-r--r-- | subx/012direct_addressing.cc | 10 | ||||
| -rw-r--r-- | subx/013immediate_addressing.cc | 89 |
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; +} |