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-rw-r--r--disasm.cpp121
-rw-r--r--test.bash5
2 files changed, 106 insertions, 20 deletions
diff --git a/disasm.cpp b/disasm.cpp
index 0e665c6..3b09c2d 100644
--- a/disasm.cpp
+++ b/disasm.cpp
@@ -161,7 +161,7 @@ enum class Condition {
kLE = 15,
};
-static inline const char *branch_instr_name_by_cond(Condition condition)
+static inline const char *bcc_mnemonic_by_condition(Condition condition)
{
switch (condition) {
case Condition::kT: return "bra"; // 60xx
@@ -181,6 +181,7 @@ static inline const char *branch_instr_name_by_cond(Condition condition)
case Condition::kGT: return "bgt"; // 6exx
case Condition::kLE: return "ble"; // 6fxx
}
+ assert(false);
return "?";
}
@@ -188,7 +189,7 @@ static void disasm_bra_bsr_bcc(
DisasmNode& node, uint16_t instr, const DataBuffer &code, const Settings &)
{
Condition condition = static_cast<Condition>((instr >> 8) & 0xf);
- const char *mnemonic = branch_instr_name_by_cond(condition);
+ const char *mnemonic = bcc_mnemonic_by_condition(condition);
// False condition Indicates BSR
node.is_call = (condition == Condition::kF);
int dispmt = static_cast<int8_t>(instr & 0xff);
@@ -229,43 +230,123 @@ static void chunk_mf000_v3000(DisasmNode& n, uint16_t i, const DataBuffer &c, co
return disasm_verbatim(n, i, c, s);
}
-static void chunk_mf000_v4000(DisasmNode& n, uint16_t i, const DataBuffer &c, const Settings &s)
+static void chunk_mf000_v4000(DisasmNode& node, uint16_t i, const DataBuffer &c, const Settings &s)
{
if (i == 0x4e70) {
- n.size = kInstructionSizeStepBytes;
- snprintf(n.mnemonic, kMnemonicBufferSize, "reset");
+ node.size = kInstructionSizeStepBytes;
+ snprintf(node.mnemonic, kMnemonicBufferSize, "reset");
return;
} else if (i == 0x4e71) {
- n.size = kInstructionSizeStepBytes;
- snprintf(n.mnemonic, kMnemonicBufferSize, "nop");
+ node.size = kInstructionSizeStepBytes;
+ snprintf(node.mnemonic, kMnemonicBufferSize, "nop");
return;
} else if (i == 0x4e73) {
- n.size = kInstructionSizeStepBytes;
- snprintf(n.mnemonic, kMnemonicBufferSize, "rte");
+ node.size = kInstructionSizeStepBytes;
+ snprintf(node.mnemonic, kMnemonicBufferSize, "rte");
return;
} else if (i == 0x4e75) {
- n.size = kInstructionSizeStepBytes;
- snprintf(n.mnemonic, kMnemonicBufferSize, "rts");
+ node.size = kInstructionSizeStepBytes;
+ snprintf(node.mnemonic, kMnemonicBufferSize, "rts");
return;
} else if (i == 0x4e76) {
- n.size = kInstructionSizeStepBytes;
- snprintf(n.mnemonic, kMnemonicBufferSize, "trapv");
+ node.size = kInstructionSizeStepBytes;
+ snprintf(node.mnemonic, kMnemonicBufferSize, "trapv");
return;
} else if (i == 0x4e77) {
- n.size = kInstructionSizeStepBytes;
- snprintf(n.mnemonic, kMnemonicBufferSize, "rtr");
+ node.size = kInstructionSizeStepBytes;
+ snprintf(node.mnemonic, kMnemonicBufferSize, "rtr");
return;
} else if ((i & 0xffc0) == 0x4e80) {
- return disasm_jsr(n, i, c, s);
+ return disasm_jsr(node, i, c, s);
} else if ((i & 0xffc0) == 0x4ec0) {
- return disasm_jmp(n, i, c, s);
+ return disasm_jmp(node, i, c, s);
}
- return disasm_verbatim(n, i, c, s);
+ return disasm_verbatim(node, i, c, s);
+}
+
+enum class OpSize {
+ kByte = 0,
+ kWord = 1,
+ kLong = 2,
+ kInvalid = 3,
+};
+
+static void disasm_subq(
+ DisasmNode& n, uint16_t instr, const DataBuffer &c, const Settings &s, int m, OpSize opsize)
+{
+ (void) m;
+ (void) opsize;
+ return disasm_verbatim(n, instr, c, s);
}
-static void chunk_mf000_v5000(DisasmNode& n, uint16_t i, const DataBuffer &c, const Settings &s)
+static void disasm_addq(
+ DisasmNode& n, uint16_t instr, const DataBuffer &c, const Settings &s, int m, OpSize opsize)
{
- return disasm_verbatim(n, i, c, s);
+ (void) m;
+ (void) opsize;
+ return disasm_verbatim(n, instr, c, s);
+}
+
+static void disasm_scc(DisasmNode& n, uint16_t instr, const DataBuffer &c, const Settings &s, int m)
+{
+ (void) m;
+ return disasm_verbatim(n, instr, c, s);
+}
+
+static inline const char *dbcc_mnemonic_by_condition(Condition condition)
+{
+ switch (condition) {
+ case Condition::kT: return "dbt"; // 50xx
+ case Condition::kF: return "dbf"; // 51xx
+ case Condition::kHI: return "dbhi"; // 52xx
+ case Condition::kLS: return "dbls"; // 53xx
+ case Condition::kCC: return "dbcc"; // 54xx
+ case Condition::kCS: return "dbcs"; // 55xx
+ case Condition::kNE: return "dbne"; // 56xx
+ case Condition::kEQ: return "dbeq"; // 57xx
+ case Condition::kVC: return "dbvc"; // 58xx
+ case Condition::kVS: return "dbvs"; // 59xx
+ case Condition::kPL: return "dbpl"; // 5axx
+ case Condition::kMI: return "dbmi"; // 5bxx
+ case Condition::kGE: return "dbge"; // 5cxx
+ case Condition::kLT: return "dblt"; // 5dxx
+ case Condition::kGT: return "dbgt"; // 5exx
+ case Condition::kLE: return "dble"; // 5fxx
+ }
+ assert(false);
+ return "?";
+}
+
+static void disasm_dbcc(DisasmNode& node, uint16_t instr, const DataBuffer &code, const Settings &)
+{
+ node.size = kInstructionSizeStepBytes * 2;
+ Condition condition = static_cast<Condition>((instr >> 8) & 0xf);
+ const char *mnemonic = dbcc_mnemonic_by_condition(condition);
+ const int regnum = (instr & 7);
+ const int16_t dispmt = GetI16BE(code.buffer + node.offset + kInstructionSizeStepBytes) +
+ kInstructionSizeStepBytes;
+ node.branch_addr = node.offset + dispmt;
+ node.has_branch_addr = true;
+ const char * const sign = dispmt >= 0 ? "+" : "";
+ snprintf(node.mnemonic, kMnemonicBufferSize, "%s", mnemonic);
+ snprintf(node.arguments, kArgsBufferSize, "%%d%d,.%s%d", regnum, sign, dispmt);
+ return;
+}
+
+static void chunk_mf000_v5000(DisasmNode& n, uint16_t instr, const DataBuffer &c, const Settings &s)
+{
+ const auto opsize = static_cast<OpSize>((instr >> 6) & 3);
+ const int m = ((instr >> 3) & 7);
+ if (opsize == OpSize::kInvalid) {
+ if (m == 1) {
+ return disasm_dbcc(n, instr, c, s);
+ }
+ return disasm_scc(n, instr, c, s, m);
+ }
+ if ((instr >> 8) & 1) {
+ return disasm_subq(n, instr, c, s, m, opsize);
+ }
+ return disasm_addq(n, instr, c, s, m, opsize);
}
static void chunk_mf000_v6000(DisasmNode& n, uint16_t i, const DataBuffer &c, const Settings &s)
diff --git a/test.bash b/test.bash
index 1ac1bb1..5b35eec 100644
--- a/test.bash
+++ b/test.bash
@@ -60,6 +60,11 @@ run_test_iterative() {
done
}
+# 50cf xxxx
+#
+run_test_simple "dbt negative displacement" "\x50\xcf\xff\xfc"
+run_test_simple "dbt positive displacement" "\x50\xcf\x01\x08"
+
# 60xx
#
run_test_simple "bras negative displacement" "\x60\xfc"
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-19 14:32:50 +0000