diff options
Diffstat (limited to 'subx')
| -rw-r--r-- | subx/022div.cc | 38 | ||||
| -rw-r--r-- | subx/031check_operands.cc | 2 |
2 files changed, 40 insertions, 0 deletions
diff --git a/subx/022div.cc b/subx/022div.cc new file mode 100644 index 00000000..0498d7ee --- /dev/null +++ b/subx/022div.cc @@ -0,0 +1,38 @@ +//: helper for division operations: sign-extend EAX into EDX + +:(before "End Initialize Op Names") +put_new(Name, "99", "sign-extend EAX into EDX (cdq)"); + +:(code) +void test_cdq() { + Reg[EAX].i = 10; + run( + "== 0x1\n" // code segment + "99\n" + ); + CHECK_TRACE_CONTENTS( + "run: sign-extend EAX into EDX\n" + "run: EDX is now 0x00000000\n" + ); +} + +:(before "End Single-Byte Opcodes") +case 0x99: { // sign-extend EAX into EDX + trace(Callstack_depth+1, "run") << "sign-extend EAX into EDX" << end(); + Reg[EDX].i = (Reg[EAX].i < 0) ? -1 : 0; + trace(Callstack_depth+1, "run") << "EDX is now 0x" << HEXWORD << Reg[EDX].u << end(); + break; +} + +:(code) +void test_cdq_negative() { + Reg[EAX].i = -10; + run( + "== 0x1\n" // code segment + "99\n" + ); + CHECK_TRACE_CONTENTS( + "run: sign-extend EAX into EDX\n" + "run: EDX is now 0xffffffff\n" + ); +} diff --git a/subx/031check_operands.cc b/subx/031check_operands.cc index 475cda5c..9590979f 100644 --- a/subx/031check_operands.cc +++ b/subx/031check_operands.cc @@ -141,6 +141,8 @@ void init_permitted_operands() { put(Permitted_operands, "5d", 0x00); put(Permitted_operands, "5e", 0x00); put(Permitted_operands, "5f", 0x00); + // sign-extend EAX into EDX + put(Permitted_operands, "99", 0x00); // return put(Permitted_operands, "c3", 0x00); |