From 6b45e0f81267be6140f0f178579494ca6d24443b Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Mon, 31 Oct 2022 19:55:32 -0700
Subject: Restructure a lot of the control registers

---
 isa/isa.h | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

(limited to 'isa/isa.h')

diff --git a/isa/isa.h b/isa/isa.h
index 69f8b2a..71f852e 100644
--- a/isa/isa.h
+++ b/isa/isa.h
@@ -26,15 +26,31 @@ const std::map<std::string, ctlreg> ctlreg_map = {
 #undef REG
 };
 
+// FLAGS and FLAGS_SAVED
+static constexpr unsigned int FLAG_DF_SHIFT = 0;
+static constexpr std::uint_fast32_t FLAG_DF = 07 << FLAG_DF_SHIFT;
+static constexpr unsigned int FLAG_IF_SHIFT = 3;
+static constexpr std::uint_fast32_t FLAG_IF = 07 << FLAG_IF_SHIFT;  // In FLAGS this is IFB, not IF
+static constexpr std::uint_fast32_t FLAG_USER_MODE = 1 << 6;
+static constexpr std::uint_fast32_t FLAG_INT_ENABLE = 1 << 7;
+static constexpr std::uint_fast32_t FLAG_INT_INHIBIT = 1 << 8;
+static constexpr std::uint_fast32_t FLAG_INT_REQUEST = 1 << 9;
+static constexpr std::uint_fast32_t FLAG_GREATER_THAN = 1 << 10;
+static constexpr std::uint_fast32_t FLAG_INT_ENABLE_DELAY = 1 << 12;
+
 // TT_BITS
 static constexpr std::uint_fast32_t TTI_FLAG = 1 << 0;
 static constexpr std::uint_fast32_t TTO_TX = 1 << 1;
 static constexpr std::uint_fast32_t TTO_FLAG = 1 << 2;
 static constexpr unsigned int TTI_DATA_SHIFT = 8;
-static constexpr unsigned int TTO_DATA_SHIFT = 16;
 static constexpr std::uint_fast32_t TTI_DATA = 0xff << TTI_DATA_SHIFT;
+static constexpr unsigned int TTO_DATA_SHIFT = 16;
 static constexpr std::uint_fast32_t TTO_DATA = 0xff << TTO_DATA_SHIFT;
 
+// TT_FLAGS
+static constexpr std::uint_fast32_t TTF_INT_ENABLE = 1 << 0;
+static constexpr std::uint_fast32_t TTF_STATUS_ENABLE = 1 << 1;
+
 struct instruction_context {
     // Known statically at decode time
     bool need_indirect_load = false;    // final_address = mem[init_address]
@@ -65,4 +81,4 @@ struct instruction_context {
     std::optional<unsigned int> mq;
 };
 
-instruction_context decode(unsigned int df, unsigned int pc, unsigned int bits, bool interrupt);
+instruction_context decode(std::uint_fast32_t flags, unsigned int pc, unsigned int bits, bool interrupt);
-- 
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