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author AJR <ajrhacker@users.noreply.github.com>2020-01-06 10:05:26 -0500
committer AJR <ajrhacker@users.noreply.github.com>2020-01-06 10:05:26 -0500
commit5a93f7903e0443a86ca020f3b769cb98f610d543 (patch)
tree41ce1f773161a214c18aee6fcf3dfc91132a3148
parentcdb95784715b109c6573a5c6a6cf3f171592b702 (diff)
rx01dasm.cpp: Add a few comments (nw)
-rw-r--r--src/devices/cpu/rx01/rx01dasm.cpp11
1 files changed, 11 insertions, 0 deletions
diff --git a/src/devices/cpu/rx01/rx01dasm.cpp b/src/devices/cpu/rx01/rx01dasm.cpp
index d78f98d3776..c7210aaf86d 100644
--- a/src/devices/cpu/rx01/rx01dasm.cpp
+++ b/src/devices/cpu/rx01/rx01dasm.cpp
@@ -93,6 +93,7 @@ offs_t rx01_disassembler::disassemble(std::ostream &stream, offs_t pc, const rx0
}
else
{
+ // Clock scratchpad address register
util::stream_format(stream, "OPEN R%d", (opcode & 074) >> 2);
return 1 | SUPPORTED;
}
@@ -100,18 +101,22 @@ offs_t rx01_disassembler::disassemble(std::ostream &stream, offs_t pc, const rx0
else switch (opcode & 074)
{
case 000: case 004: case 010: case 014: case 020: case 024: case 030:
+ // IOB flip-flops for drive or interface
util::stream_format(stream, "%s IOB%d", BIT(opcode, 1) ? "SET" : "CLR", (opcode & 074) >> 2);
return 1 | SUPPORTED;
case 034:
+ // Drive select
util::stream_format(stream, "UNIT %s", s_0_or_1[BIT(opcode, 1)]);
return 1 | SUPPORTED;
case 040:
+ // Head load/unload
util::stream_format(stream, "%sHD", BIT(opcode, 1) ? "LD" : "UN");
return 1 | SUPPORTED;
case 044:
+ // Clock buffer address register
if (BIT(opcode, 1))
stream << "INCR BAR";
else
@@ -119,10 +124,12 @@ offs_t rx01_disassembler::disassemble(std::ostream &stream, offs_t pc, const rx0
return 1 | SUPPORTED;
case 050:
+ // Sector data buffer write
util::stream_format(stream, "%s WRTBUF", BIT(opcode, 0) ? "START" : "FIN");
return 1 | SUPPORTED;
case 054:
+ // Shift/preset CRC
if (BIT(opcode, 0))
util::stream_format(stream, "%sCRC", BIT(opcode, 1) ? "PRE" : "DAT");
else
@@ -130,14 +137,17 @@ offs_t rx01_disassembler::disassemble(std::ostream &stream, offs_t pc, const rx0
return 1 | SUPPORTED;
case 060:
+ // Clock flag flip-flop (J/K)
util::stream_format(stream, "%s FLAG", s_flag_control[opcode & 3]);
return 1 | SUPPORTED;
case 064:
+ // Write to scratchpad
stream << "LSP";
return 1 | SUPPORTED;
case 070:
+ // Clock counter
if (BIT(opcode, 1))
{
stream << "ICT";
@@ -155,6 +165,7 @@ offs_t rx01_disassembler::disassemble(std::ostream &stream, offs_t pc, const rx0
}
case 074:
+ // Clock shift register
if (!BIT(opcode, 0))
util::stream_format(stream, "ROTATE %s", s_0_or_1[BIT(opcode, 1)]);
else if (BIT(opcode, 1))