Implement march testing for SRAM

Probably not a great test set yet, but this is a start.

emulator-patches/kinetoscope.c

@@ -39,6 +39,7 @@
 #define CMD_FLIP_REGION 0x04
 #define CMD_GET_ERROR   0x05
 #define CMD_CONNECT_NET 0x06
+#define CMD_MARCH_TEST  0x07
 
 // NOTE: The addresses sent to us are all relative to the base of 0xA13000.
 // So we only check the offset from there.  All addresses are even because the
@@ -365,6 +366,54 @@ static void get_video_list() {
   }
 }
 
+#define SRAM_BANK_SIZE_BYTES (1 << 20)
+
+// Write a test pattern that the Sega can read and verify.
+static void sram_march_test(int pass) {
+  uint32_t offset = (pass & 1) * SRAM_BANK_SIZE_BYTES;
+
+  switch (pass) {
+    case 0:
+    case 1:
+    case 2:
+    case 3:
+    case 4:
+    case 5:
+    case 6:
+    case 7:
+    case 8:
+    case 9:
+    case 10:
+    case 11:
+    case 12:
+    case 13:
+    case 14:
+    case 15:
+      for (int i = 0; i < SRAM_BANK_SIZE_BYTES; ++i) {
+        int bit = (i + pass / 2) % 8;
+        uint8_t data = 1 << bit;
+        write_sram(offset++, &data, 1);
+      }
+      break;
+
+    case 16:
+    case 17:
+      for (int i = 0; i < SRAM_BANK_SIZE_BYTES; ++i) {
+        uint8_t data = i & 0xff;
+        write_sram(offset++, &data, 1);
+      }
+      break;
+
+    case 18:
+    case 19:
+      for (int i = 0; i < SRAM_BANK_SIZE_BYTES; ++i) {
+        uint8_t data = (i & 0xff) ^ 0xff;
+        write_sram(offset++, &data, 1);
+      }
+      break;
+  }
+}
+
 static void execute_command() {
   if (global_command == CMD_ECHO) {
     // Used by the ROM to check for the necessary streaming hardware.
@@ -389,6 +438,9 @@ static void execute_command() {
   } else if (global_command == CMD_CONNECT_NET) {
     printf("Kinetoscope: CMD_CONNECT_NET\n");
     // Nothing to do: already connected.
+  } else if (global_command == CMD_MARCH_TEST) {
+    printf("Kinetoscope: CMD_MARCH_TEST\n");
+    sram_march_test(global_arg);
   } else {
     report_error("Unrecognized command 0x%02X!", global_command);
   }

firmware/firmware.ino

@@ -287,6 +287,10 @@ static void process_command(uint8_t command, uint8_t arg) {
       }
       break;
 
+    case KINETOSCOPE_CMD_MARCH_TEST:
+      sram_march_test(arg);
+      break;
+
     default: {
       report_error("Unrecognized command 0x%02X!", command);
       break;

firmware/registers.h

@@ -29,6 +29,7 @@
 #define KINETOSCOPE_CMD_FLIP_REGION 0x04  // Switch SRAM banks for streaming
 #define KINETOSCOPE_CMD_GET_ERROR   0x05  // Load error information into SRAM
 #define KINETOSCOPE_CMD_CONNECT_NET 0x06  // Connect/reconnect to the network
+#define KINETOSCOPE_CMD_MARCH_TEST  0x07  // Perform a march test on SRAM
 
 void registers_init();
 

firmware/sram.cc

@@ -16,6 +16,8 @@
 static int leftover = -1;
 static int active_bank_pin = -1;
 
+#define SRAM_BANK_SIZE_BYTES (1 << 20)
+
 // Explicitly unrolled loop for 16 bits of data.
 #define X16(a) { a; a; a; a; a; a; a; a; a; a; a; a; a; a; a; a; }
 static inline void sram_write_word(uint16_t word_data) {
@@ -110,3 +112,51 @@ void sram_flush_and_release_bank() {
 
   leftover = -1;
 }
+
+// Write a test pattern that the Sega can read and verify.
+void sram_march_test(int pass) {
+  sram_start_bank(pass & 1);
+
+  switch (pass) {
+    case 0:
+    case 1:
+    case 2:
+    case 3:
+    case 4:
+    case 5:
+    case 6:
+    case 7:
+    case 8:
+    case 9:
+    case 10:
+    case 11:
+    case 12:
+    case 13:
+    case 14:
+    case 15:
+      for (int i = 0; i < SRAM_BANK_SIZE_BYTES; ++i) {
+        int bit = (i + pass / 2) % 8;
+        uint8_t data = 1 << bit;
+        sram_write(&data, 1);
+      }
+      break;
+
+    case 16:
+    case 17:
+      for (int i = 0; i < SRAM_BANK_SIZE_BYTES; ++i) {
+        uint8_t data = i & 0xff;
+        sram_write(&data, 1);
+      }
+      break;
+
+    case 18:
+    case 19:
+      for (int i = 0; i < SRAM_BANK_SIZE_BYTES; ++i) {
+        uint8_t data = (i & 0xff) ^ 0xff;
+        sram_write(&data, 1);
+      }
+      break;
+  }
+
+  sram_flush_and_release_bank();
+}

firmware/sram.h

@@ -17,4 +17,6 @@ void sram_start_bank(int bank);
 void sram_write(const uint8_t *data, int num_bytes);
 void sram_flush_and_release_bank();
 
+void sram_march_test(int pass);
+
 #endif // _KINETOSCOPE_SRAM_H

software/build.sh

@@ -45,7 +45,7 @@ docker run \
   -v "$repo_root":/src \
   -u $(id -u):$(id -g) \
   -w "/src/$relative_dir" \
-  ghcr.io/stephane-d/sgdk:latest
+  ghcr.io/stephane-d/sgdk:working
 
 # SGDK's compiler makes the output executable, but that's not appropriate.
 chmod 644 $this_dir/out/rom.bin