SCSI: Implement MODE SELECT(6) parameter parsing and unit tests

CMakeLists.txt

@@ -50,6 +50,7 @@ if (EMSCRIPTEN)
 endif()
 
 option(DPPC_BUILD_PPC_TESTS  "Build PowerPC tests" OFF)
+option(DPPC_BUILD_SCSI_TESTS "Build SCSI tests" OFF)
 option(DPPC_BUILD_BENCHMARKS "Build benchmarking programs" OFF)
 
 option(DPPC_68K_DEBUGGER   "Enable 68k debugging" OFF)
@@ -231,4 +232,14 @@ if (DPPC_BUILD_PPC_TESTS)
         $<TARGET_FILE_DIR:${PROJECT_NAME}>)
 endif()
 
+if (DPPC_BUILD_SCSI_TESTS)
+    file(GLOB SCSI_TEST_SOURCES "${PROJECT_SOURCE_DIR}/devices/common/scsi/test/*.cpp")
+    add_executable(testscsi ${SCSI_TEST_SOURCES}
+                            "${PROJECT_SOURCE_DIR}/devices/common/scsi/scsiparseutils.cpp")
+    target_include_directories(testscsi PRIVATE
+                            "${PROJECT_SOURCE_DIR}"
+                            "${PROJECT_SOURCE_DIR}/thirdparty/loguru/")
+    target_link_libraries(testscsi PRIVATE loguru ${CMAKE_DL_LIBS} ${CMAKE_THREAD_LIBS_INIT})
+endif()
+
 install (TARGETS dingusppc DESTINATION ${PROJECT_SOURCE_DIR}/build)

devices/common/scsi/scsicdrom.cpp

@@ -23,6 +23,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <devices/common/scsi/scsi.h>
 #include <devices/common/scsi/scsicdrom.h>
+#include <devices/common/scsi/scsiparseutils.h>
 #include <devices/deviceregistry.h>
 #include <loguru.hpp>
 #include <machines/machineproperties.h>
@@ -233,8 +234,16 @@ void ScsiCdrom::mode_select_6(uint8_t param_len)
     std::memset(&this->data_buf[0], 0, 512);
 
     this->post_xfer_action = [this]() {
-        // TODO: parse the received mode parameter list here
-        LOG_F(INFO, "Mode Select: received mode parameter list");
+        ModeSelectData parsed;
+        parse_mode_select_6(this->data_buf, this->incoming_size,
+            this->name.c_str(), parsed);
+
+        // TODO: if the block descriptor requests 512-byte blocks (parsed.bd_block_len == 512),
+        // we should switch block_size so subsequent READs use 512-byte LBA addressing.
+        // This requires BlockStorageDevice::set_block_size() to also update block_size
+        // (currently it only sets raw_blk_size), and size_blocks must be recalculated.
+        // Classic Mac OS drivers may not need this (they subdivide 2048-byte sectors
+        // internally), but some drivers may depend on it.
     };
 
     this->switch_phase(ScsiPhase::DATA_OUT);

devices/common/scsi/scsihd.cpp

@@ -24,6 +24,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <core/timermanager.h>
 #include <devices/common/scsi/scsi.h>
 #include <devices/common/scsi/scsihd.h>
+#include <devices/common/scsi/scsiparseutils.h>
 #include <devices/deviceregistry.h>
 #include <loguru.hpp>
 #include <machines/machineproperties.h>
@@ -183,7 +184,9 @@ void ScsiHardDisk::mode_select_6(uint8_t param_len) {
     std::memset(&this->data_buf[0], 0xDD, this->sector_size);
 
     this->post_xfer_action = [this]() {
-        // TODO: parse the received mode parameter list here
+        ModeSelectData parsed;
+        parse_mode_select_6(this->data_buf, this->incoming_size,
+            this->name.c_str(), parsed);
     };
 
     this->switch_phase(ScsiPhase::DATA_OUT);

devices/common/scsi/scsiparseutils.cpp

@@ -0,0 +1,98 @@
+/*
+DingusPPC - The Experimental PowerPC Macintosh emulator
+Copyright (C) 2018-26 The DingusPPC Development Team
+          (See CREDITS.MD for more details)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/** @file SCSI Mode Select parameter list parsing utilities. */
+
+#include <devices/common/scsi/scsiparseutils.h>
+#include <loguru.hpp>
+
+#include <cstring>
+
+int parse_mode_select_6(const uint8_t* data, int data_len, const char* dev_name,
+                        ModeSelectData& result)
+{
+    std::memset(&result, 0, sizeof(result));
+
+    // Need at least the 4-byte mode parameter header
+    if (data_len < 4) {
+        if (dev_name)
+            LOG_F(WARNING, "%s: MODE SELECT parameter list too short (%d bytes)",
+                dev_name, data_len);
+        return -1;
+    }
+
+    // Parse the mode parameter header (4 bytes for MODE SELECT(6))
+    // Byte 0: mode data length (reserved for MODE SELECT, should be 0)
+    result.medium_type   = data[1];
+    result.device_param  = data[2];
+    result.block_desc_len = data[3];
+
+    if (dev_name)
+        LOG_F(INFO, "%s: MODE SELECT medium_type=%d, dev_param=0x%02X, bdl=%d",
+            dev_name, result.medium_type, result.device_param, result.block_desc_len);
+
+    // Validate block descriptor length fits in the data
+    if (4 + result.block_desc_len > data_len) {
+        if (dev_name)
+            LOG_F(WARNING, "%s: MODE SELECT block descriptor overflows data",
+                dev_name);
+        return -1;
+    }
+
+    // Parse block descriptor if present
+    if (result.block_desc_len >= 8) {
+        result.bd_num_blocks = (data[5] << 16) | (data[6] << 8) | data[7];
+        result.bd_block_len  = (data[9] << 16) | (data[10] << 8) | data[11];
+        if (dev_name && result.bd_num_blocks)
+            LOG_F(INFO, "%s: MODE SELECT block descriptor: num_blocks=%d, block_len=%d",
+                dev_name, result.bd_num_blocks, result.bd_block_len);
+    }
+
+    // Parse mode pages
+    int offset = 4 + result.block_desc_len;
+    result.num_pages = 0;
+
+    while (offset + 1 < data_len) {
+        uint8_t page_code = data[offset] & 0x3F;
+        uint8_t page_len  = data[offset + 1];
+
+        if (offset + 2 + page_len > data_len) {
+            if (dev_name)
+                LOG_F(WARNING, "%s: MODE SELECT page 0x%02X truncated "
+                    "(need %d bytes at offset %d, only %d available)",
+                    dev_name, page_code, page_len, offset + 2, data_len - offset - 2);
+            return -1;
+        }
+
+        if (result.num_pages < ModeSelectData::MAX_PAGES) {
+            result.pages[result.num_pages].page_code   = page_code;
+            result.pages[result.num_pages].page_len    = page_len;
+            result.pages[result.num_pages].data_offset = offset + 2;
+            result.num_pages++;
+        }
+
+        if (dev_name)
+            LOG_F(INFO, "%s: MODE SELECT page 0x%02X, length %d",
+                dev_name, page_code, page_len);
+
+        offset += 2 + page_len;
+    }
+
+    return result.num_pages;
+}

devices/common/scsi/scsiparseutils.h

@@ -0,0 +1,60 @@
+/*
+DingusPPC - The Experimental PowerPC Macintosh emulator
+Copyright (C) 2018-26 The DingusPPC Development Team
+          (See CREDITS.MD for more details)
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/** @file SCSI Mode Select parameter list parsing utilities. */
+
+#ifndef SCSI_PARSE_UTILS_H
+#define SCSI_PARSE_UTILS_H
+
+#include <cinttypes>
+
+/** Result of parsing a mode page entry. */
+struct ModePageParsed {
+    uint8_t page_code;
+    uint8_t page_len;
+    int     data_offset; // byte offset to page data (past page_code + page_len)
+};
+
+/** Parsed MODE SELECT(6) parameter list. */
+struct ModeSelectData {
+    uint8_t  medium_type;
+    uint8_t  device_param;
+    uint8_t  block_desc_len;
+
+    // Block descriptor fields (valid when block_desc_len >= 8)
+    uint32_t bd_num_blocks;
+    uint32_t bd_block_len;
+
+    int      num_pages;
+    static const int MAX_PAGES = 16;
+    ModePageParsed pages[MAX_PAGES];
+};
+
+/** Parse a MODE SELECT(6) parameter list.
+ *
+ *  @param data       Pointer to the parameter list data.
+ *  @param data_len   Length of the parameter list in bytes.
+ *  @param dev_name   Device name for log messages (may be nullptr to suppress logging).
+ *  @param result     Parsed result output.
+ *  @return           Number of pages parsed, or -1 on structural error.
+ */
+int parse_mode_select_6(const uint8_t* data, int data_len, const char* dev_name,
+                        ModeSelectData& result);
+
+#endif // SCSI_PARSE_UTILS_H