From d3c913e38492dfd006d2e65534e9fd8f2dde85f2 Mon Sep 17 00:00:00 2001
From: joevt <joevt@shaw.ca>
Date: Sun, 10 Mar 2024 01:02:45 -0800
Subject: [PATCH] scsicdrom: Cleanup.

- Use macros for reading 2 byte or 4 byte big endian data. block_size is assumed to be < 64K so WRITE_DWORD_BE_A will write two leading zeros.
- Scalar pass by value parameters don't need to be const.
- Remove some unnecessary locals.
---
 devices/common/scsi/scsicdrom.cpp | 27 +++++++++------------------
 1 file changed, 9 insertions(+), 18 deletions(-)

diff --git a/devices/common/scsi/scsicdrom.cpp b/devices/common/scsi/scsicdrom.cpp
index 0a8f367..a8411ee 100644
--- a/devices/common/scsi/scsicdrom.cpp
+++ b/devices/common/scsi/scsicdrom.cpp
@@ -38,7 +38,7 @@ ScsiCdrom::ScsiCdrom(std::string name, int my_id) : CdromDrive(), ScsiDevice(nam
 
 void ScsiCdrom::process_command()
 {
-    uint32_t lba, xfer_len;
+    uint32_t lba;
 
     this->pre_xfer_action  = nullptr;
     this->post_xfer_action = nullptr;
@@ -112,12 +112,11 @@ void ScsiCdrom::process_command()
         this->read_capacity_10();
         break;
     case ScsiCommand::READ_10:
-        lba      = READ_DWORD_BE_U(&cmd[2]);
-        xfer_len = READ_WORD_BE_U(&cmd[7]);
+        lba = READ_DWORD_BE_U(&cmd[2]);
         if (cmd[1] & 1) {
             ABORT_F("%s: RelAdr bit set in READ_10", this->name.c_str());
         }
-        read(lba, xfer_len, 10);
+        read(lba, READ_WORD_BE_U(&cmd[7]), 10);
         break;
     case ScsiCommand::WRITE_10:
         this->illegal_command(cmd);
@@ -177,7 +176,7 @@ bool ScsiCdrom::get_more_data() {
     return this->data_size != 0;
 }
 
-void ScsiCdrom::read(const uint32_t lba, uint16_t nblocks, const uint8_t cmd_len)
+void ScsiCdrom::read(uint32_t lba, uint16_t nblocks, uint8_t cmd_len)
 {
     if (cmd_len == 6 && nblocks == 0)
         nblocks = 256;
@@ -233,17 +232,15 @@ void ScsiCdrom::mode_sense_6()
     uint8_t page_code = this->cmd_buf[2] & 0x3F;
     //uint8_t alloc_len = this->cmd_buf[4];
 
-    int num_blocks = this->size_blocks;
-
     this->data_buf[ 0] =   13; // initial data size
     this->data_buf[ 1] =    0; // medium type
     this->data_buf[ 2] = 0x80; // medium is write protected
     this->data_buf[ 3] =    8; // block description length
 
     this->data_buf[ 4] =    0; // density code
-    this->data_buf[ 5] = (num_blocks >> 16) & 0xFFU;
-    this->data_buf[ 6] = (num_blocks >>  8) & 0xFFU;
-    this->data_buf[ 7] = (num_blocks      ) & 0xFFU;
+    this->data_buf[ 5] = (this->size_blocks >> 16) & 0xFFU;
+    this->data_buf[ 6] = (this->size_blocks >>  8) & 0xFFU;
+    this->data_buf[ 7] = (this->size_blocks      ) & 0xFFU;
     this->data_buf[ 8] =    0;
     this->data_buf[ 9] =    0;
     this->data_buf[10] = (this->block_size >> 8) & 0xFFU;
@@ -386,14 +383,8 @@ void ScsiCdrom::read_capacity_10()
 
     int last_lba = this->size_blocks - 1;
 
-    this->data_buf[0] = (last_lba >> 24) & 0xFFU;
-    this->data_buf[1] = (last_lba >> 16) & 0xFFU;
-    this->data_buf[2] = (last_lba >>  8) & 0xFFU;
-    this->data_buf[3] = (last_lba >>  0) & 0xFFU;
-    this->data_buf[4] = 0;
-    this->data_buf[5] = 0;
-    this->data_buf[6] = (this->block_size >> 8) & 0xFFU;
-    this->data_buf[7] = this->block_size & 0xFFU;
+    WRITE_DWORD_BE_A(&this->data_buf[0], last_lba);
+    WRITE_DWORD_BE_A(&this->data_buf[4], this->block_size);
 
     this->bytes_out  = 8;
     this->msg_buf[0] = ScsiMessage::COMMAND_COMPLETE;