From 9fbacc2a325fdb96daf6c9e1afa6f0ce5a5853c4 Mon Sep 17 00:00:00 2001
From: Mikael Pettersson <mikpelinux@gmail.com>
Date: Sat, 22 Dec 2018 17:24:29 +0100
Subject: [PATCH] sim: minor updates

---
 sim/pdp10-core.h | 20 +++++++++++++++-----
 sim/pdp10-ea.h   | 13 ++++++++++++-
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/sim/pdp10-core.h b/sim/pdp10-core.h
index 77b8140..767dd79 100644
--- a/sim/pdp10-core.h
+++ b/sim/pdp10-core.h
@@ -90,13 +90,23 @@ static inline unsigned int BIT36(pdp10_uint36_t X, unsigned int BIT)
     return BITS36(X, BIT, BIT);
 }
 
-typedef uint32_t pdp10_vaddr_t; /* 30 bits: section number, section offset */
-typedef uint32_t pdp10_pc_t; /* 31 bits: global flag, vaddr */
+typedef uint32_t pdp10_vaddr_t; /* 30 bits: 12-bit section number, 18-bit section offset */
 
 struct pdp10_cpu {
-    pdp10_pc_t PC;
-    pdp10_uint36_t AC[017];
-    unsigned int flags; /* 13 bits */
+    pdp10_vaddr_t PC;
+    pdp10_uint36_t AC[017]; /* copy of ACS[CAB] */
+    pdp10_uint36_t ACS[8][017];
+    unsigned int flags:13;
+    unsigned int CAB:3; /* Current AC Block */
+    /*
+     * Previous Context
+     */
+    unsigned int PCS:12; /* Previous Context Section */
+    unsigned int PCU:1; /* Previous Context User */
+    unsigned int PAB:3; /* Previous AC Block */
+    /*
+     * Memory
+     */
     struct pdp10_vmem vmem;
 };
 
diff --git a/sim/pdp10-ea.h b/sim/pdp10-ea.h
index 2212df9..e58be19 100644
--- a/sim/pdp10-ea.h
+++ b/sim/pdp10-ea.h
@@ -24,8 +24,19 @@
 
 /* This performs Effective Address Calculation, but not Instruction Fetch
  * or looping on XCT instructions; the caller is assumed to handle that.
- * Returns (uint64_t)-1 on failure (page fault), a pdp10_uint36_t word on success.
+ * Returns (uint64_t)-1 on failure (page fault), otherwise a pdp10_vaddr_t
+ * (30 bits) and a 1-bit local(0)/global(1) flag in the MSB (2^30).
  */
 uint64_t pdp10_ea(struct pdp10_cpu *cpu, uint64_t MB);
 
+static inline int pdp10_ea_is_page_fault(uint64_t ea)
+{
+    return ea == (uint64_t)-1;
+}
+
+static inline int pdp10_ea_is_global(uint64_t ea)
+{
+    return ea & (1UL << 30);
+}
+
 #endif /* PDP10_EA_H */