Long standing assembler bugs fixed, new path system. Make compatibility update.

2026-08-14 16:53:28 -04:00
parent 94b3a7af28
commit 638b68b25c
32 changed files with 1002 additions and 273 deletions
@@ -8,10 +8,52 @@
 #ifndef ASSEMBLY_H
 #define ASSEMBLY_H

+// ---- The SplitBit binary format ----
+//
+// A binary starts with a file header, then the Program Segment, then the Data
+// Segment. All multi byte numbers are stored most significant byte first.
+//
+//   Offset  Size  Field
+//   0       4     "SPBT", so a file that is not a SplitBit binary is spotted at once
+//   4       1     Format version
+//   5       4     Required feature flags
+//   9       3     "PRG"
+//   12      2     Program Segment length
+//   14      N     Program Segment
+//   ..      3     "DAT"
+//   ..      2     Data Segment length
+//   ..      M     Data Segment
+//
+// The feature flags are how a binary says it needs something the base machine does
+// not provide, so that an emulator which cannot provide it refuses to run the binary
+// rather than quietly doing the wrong thing. No features are defined yet; the field
+// is here so that adding one later does not need another format version.
+
+#define SPLITBIT_MAGIC "SPBT"
+#define SPLITBIT_MAGIC_LENGTH 4
+#define SPLITBIT_FORMAT_VERSION 1
+#define SPLITBIT_FLAGS_LENGTH 4
+#define SEGMENT_MARKER_LENGTH 3
+#define SEGMENT_LENGTH_BYTES 2
+
+// Everything the format costs a file, on top of the two segments themselves.
+#define SPLITBIT_HEADER_BYTES (SPLITBIT_MAGIC_LENGTH + 1 + SPLITBIT_FLAGS_LENGTH \
+                               + 2 * (SEGMENT_MARKER_LENGTH + SEGMENT_LENGTH_BYTES))
+
+// Features this build of the emulator can provide. A binary asking for anything
+// outside this set is refused.
+#define SPLITBIT_FEATURES_SUPPORTED 0x00000000u
+
+// Features the assembler currently needs to ask for. Nothing, so far.
+#define SPLITBIT_FEATURES_REQUIRED 0x00000000u
+
 const char* getMnemonic(uint8_t opcode);

 uint8_t getOpcode(char* mnemonic);

-int instructionTakesDataPointer(uint8_t opcode);
+// How many Data Pointer selector bytes follow the given opcode. Never more than two.
+#define MAX_DATA_POINTER_OPERANDS 2
+
+int dataPointerOperands(uint8_t opcode);

 #endif // CPU_H