From 7ea9e4442b880afa35bf4006c2b0c7f18632202b Mon Sep 17 00:00:00 2001
From: Folkert van Heusden <mail@vanheusden.com>
Date: Sun, 6 Apr 2025 19:40:07 +0200
Subject: [PATCH] keep track of memory writes

---
 CMakeLists.txt    |  1 +
 PDP11/pdp11_cpu.c | 24 ++++++++++++++++++++++++
 PDP11/test.c      | 19 ++++++++++++++++---
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 120da396..1e0b1894 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -94,6 +94,7 @@ if (NOT CMAKE_CONFIGURATION_TYPES)
         message(STATUS "CMAKE_BUILD_TYPE is ${CMAKE_BUILD_TYPE}")
     endif (NOT CMAKE_BUILD_TYPE)
 endif ()
+set(CMAKE_BUILD_TYPE "RelWithDebInfo")
 
 # SIMH_SYSTEM_ID: Roughly analogous to the autoconf system triple. Used (almost exclusively)
 # as part of the dependencies' top-level directory name.
diff --git a/PDP11/pdp11_cpu.c b/PDP11/pdp11_cpu.c
index 54669379..b30e82df 100644
--- a/PDP11/pdp11_cpu.c
+++ b/PDP11/pdp11_cpu.c
@@ -279,6 +279,17 @@ typedef struct {
 
 /* Global state */
 
+struct __mem_writes {
+	int32_t addr;
+	uint16_t data;
+} *mem_writes;
+int n_mem_writes = 0;
+
+void init_mem_writes()
+{
+	mem_writes = (struct __mem_writes *)malloc(sizeof(struct __mem_writes) * 256);
+}
+
 uint16 *M = NULL;                                       /* memory */
 int32 REGFILE[6][2] = { {0} };                          /* R0-R5, two sets */
 int32 STACKFILE[4] = { 0 };                             /* SP, four modes */
@@ -2780,6 +2791,7 @@ if ((va & 1) && CPUT (HAS_ODD)) {                       /* odd address? */
     ABORT (TRAP_ODD);
     }
 pa = relocW (va);                                       /* relocate */
+
 if (BPT_SUMM_WR &&
     (sim_brk_test (va & 0177777, BPT_WRVIR) ||
      sim_brk_test (pa, BPT_WRPHY)))                     /* write breakpoint? */
@@ -2818,9 +2830,21 @@ if (BPT_SUMM_WR &&
 PWriteW (data, pa);
 }
 
+void reset_mem_writes()
+{
+	n_mem_writes = 0;
+}
+
 void PWriteW (int32 data, int32 pa)
 {
 if (ADDR_IS_MEM (pa)) {                                 /* memory address? */
+
+	if (data > 0xffff)
+		printf("FAIL %x\n", data);
+	mem_writes[n_mem_writes].addr = pa;
+	mem_writes[n_mem_writes].data = data;
+	n_mem_writes++;
+
     WrMemW (pa, data);
     return;
     }
diff --git a/PDP11/test.c b/PDP11/test.c
index f36c84f5..c0d483a5 100644
--- a/PDP11/test.c
+++ b/PDP11/test.c
@@ -21,6 +21,15 @@ extern DEVICE cpu_dev;
 extern int32 STACKFILE[4];
 extern int32 sim_interval;
 
+struct __mem_writes {
+        int32_t addr;
+        uint16_t data;
+};
+extern struct __mem_writes *mem_writes;
+extern int n_mem_writes;
+extern void reset_mem_writes();
+extern void init_mem_writes();
+
 struct mem_t {
 	uint32_t addr;
 	uint16_t value;
@@ -123,12 +132,12 @@ json_t *generate_test(uint16_t instruction, int *const id, struct mem_t *mem, si
 
 	json_t *memory_o = json_array();
 
-	for(size_t i=0; i<n_mem; i++) {
+	for(int i=0; i<n_mem_writes; i++) {
 		char buffer[16];
-		sprintf(buffer, "%06o", mem[i].addr);
+		sprintf(buffer, "%06o", mem_writes[i].addr);
 
 		json_t *get_mem = json_object();
-		json_object_set(get_mem, buffer, json_integer(PReadW(mem[i].addr)));
+		json_object_set(get_mem, buffer, json_integer(mem_writes[i].data));
 		json_array_append_new(memory_o, get_mem);
 	}
 
@@ -153,6 +162,8 @@ void init_simh()
 	// reset_all(0);  is this required?
 	cpu_reset(&cpu_dev);
 	sim_interval = 32767;
+
+	reset_mem_writes();
 }
 
 void randomize_registers_all_values()
@@ -545,6 +556,8 @@ void produce_validation_tests()
 {
 	srand(123);  // for reproducability
 
+	init_mem_writes();
+
 	generate_test_values();
 
 	emit_branch_instructions();  // conditional_branch_instructions*