From ff66523bb076a246c2fc159f0f76947bd6f84fc1 Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Sat, 29 Oct 2022 12:55:08 -0700
Subject: Control register values should not be "unsigned int"

---
 io/event.h        |  7 +++---
 io/model.cpp      |  2 +-
 io/model.h        |  5 ++++-
 isa/checker.h     |  3 ++-
 isa/decode.cpp    | 19 +++++++++++++++++
 isa/isa.h         |  3 ++-
 programs/echo.pal | 64 +++++--------------------------------------------------
 7 files changed, 37 insertions(+), 66 deletions(-)

diff --git a/io/event.h b/io/event.h
index 02f3fab..2da3323 100644
--- a/io/event.h
+++ b/io/event.h
@@ -1,14 +1,15 @@
 #pragma once
 
+#include <cstdint>
 #include <map>
 
 #include "isa/isa.h"
 
 struct event {
     ctlreg reg;
-    unsigned int mask;
-    unsigned int value;
-    event(ctlreg reg, unsigned int value, unsigned int mask=~0)
+    std::uint_fast32_t mask;
+    std::uint_fast32_t value;
+    event(ctlreg reg, std::uint_fast32_t value, std::uint_fast32_t mask=~0)
         : reg(reg)
         , mask(mask)
         , value(value)
diff --git a/io/model.cpp b/io/model.cpp
index d6e36f9..4b37be4 100644
--- a/io/model.cpp
+++ b/io/model.cpp
@@ -6,7 +6,7 @@
 #include "io/model.h"
 #include "isa/isa.h"
 
-bool iomodel::interact(std::array<unsigned int, NUM_CTLREGS> &ctlregs) {
+bool iomodel::interact(std::array<std::uint_fast32_t, NUM_CTLREGS> &ctlregs) {
     auto [ebegin, eend] = log.equal_range(time);
     for (auto e = ebegin; e != eend; ++e) {
         auto &r = ctlregs[e->second.reg];
diff --git a/io/model.h b/io/model.h
index c7199ea..8758a43 100644
--- a/io/model.h
+++ b/io/model.h
@@ -2,6 +2,7 @@
 
 #include <array>
 #include <cstdint>
+#include <istream>
 
 #include "io/event.h"
 #include "isa/isa.h"
@@ -11,5 +12,7 @@ struct iomodel {
 
     event_log log;
     std::uint64_t time = 0;
-    bool interact(std::array<unsigned int, NUM_CTLREGS> &ctlregs);
+    bool interact(std::array<std::uint_fast32_t, NUM_CTLREGS> &ctlregs);
+
+    void load_evt(std::istream &fh);
 };
diff --git a/isa/checker.h b/isa/checker.h
index 332c483..571bbc8 100644
--- a/isa/checker.h
+++ b/isa/checker.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <array>
+#include <cstdint>
 #include <map>
 
 #include "io/model.h"
@@ -41,7 +42,7 @@ struct checker {
     unsigned int link = 0;
     unsigned int mq = 0;
     unsigned int pc = 00200;
-    std::array<unsigned int, NUM_CTLREGS> ctlregs;
+    std::array<std::uint_fast32_t, NUM_CTLREGS> ctlregs;
     iomodel &system;
     instruction_context inst;
     funcmem mem;
diff --git a/isa/decode.cpp b/isa/decode.cpp
index 4af9a0d..9563327 100644
--- a/isa/decode.cpp
+++ b/isa/decode.cpp
@@ -140,6 +140,25 @@ instruction_context decode(unsigned int dfifb, unsigned int pc, unsigned int bit
                             break;
                     }
                     break;
+                case 003:
+                    // KEYBOARD
+                    switch (bits & 07) {
+                        case 1:
+                            // KSF skip if TTI flag is set
+                            inst.read_ctlreg = TT_BITS;
+                            inst.possibly_redirects = true;
+                            inst.ef = [](auto &ctx) {
+                                if (ctx.ctlval.value() & TTI_FLAG)
+                                    ctx.next_pc = (ctx.next_pc & ~07777) | ((ctx.next_pc + 1) & 07777);
+                            };
+                            break;
+                        default:
+                            inst.ef = [bits](auto &ctx) {
+                                std::cerr << "unimplemented IOT KB suboperation " << (bits & 07) << "\n";
+                                assert(false);
+                            };
+                    }
+                    break;
                 case 004:
                     // TELETYPE TELEPRINTER/PUNCH
                     switch (bits & 07) {
diff --git a/isa/isa.h b/isa/isa.h
index 1ad5a77..84a783c 100644
--- a/isa/isa.h
+++ b/isa/isa.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdint>
 #include <functional>
 #include <optional>
 
@@ -49,7 +50,7 @@ struct instruction_context {
     unsigned int next_pc;                       // includes IF
     std::optional<unsigned int> init_address;   // includes DF
     std::optional<unsigned int> final_address;  // includes DF
-    std::optional<unsigned int> ctlval;
+    std::optional<std::uint_fast32_t> ctlval;   // control registers may be larger than 16 bits (e.g. TT_BITS)
     std::optional<unsigned int> data;
     std::optional<unsigned int> acc;
     std::optional<bool> link;
diff --git a/programs/echo.pal b/programs/echo.pal
index 16d8fda..4e59623 100644
--- a/programs/echo.pal
+++ b/programs/echo.pal
@@ -1,67 +1,13 @@
 / vim: set sw=8 noexpandtab :
 
-*000
-
-INTRET,	0
-	JMP GOTINT
-
-INPUTY,	1000	/ Address of youngest byte in input buffer
-INPUTO,	1000	/ Address of oldest byte in input buffer
-
 *200
-
-/ Main program enables keyboard interrupt, then enters echo loop
-	KIE
-	ION
-LOOP,	TSF		/ Call ECHO if printer is ready
+LOOP,	TSF
 	JMS ECHO
 	JMP LOOP
 
 ECHO,	0
-	TAD INPUTO
-	CMA IAC		/ Negate
-	TAD INPUTY
-	SNA		/ Abandon echo if input buffer is empty (n.b. or full, because we don't have wrap bits)
-	JMP I ECHO
-	TAD I INPUTO	/ Read from input buffer
-	TLS		/ Print
-	JMS FIXO
+WAIT,	KSF
+	JMP WAIT
+	KRB
+	TLS
 	JMP I ECHO
-
-GOTINT,	KSF		/ Skip reading keyboard if nothing was typed
-	JMP NOIN
-	DCA SAVED
-	KRB		/ Read from keyboard
-	DCA I INPUTY	/ Write to input buffer
-	JMS FIXY
-	CLA
-	TAD SAVED
-NOIN,	RMF
-	ION
-	JMP I INTRET
-
-/ Wrap INPUTY pointer at 2000 back to 1000
-FIXY,	0
-	TAD INPUTY
-	TAD [-2000]
-	SZA
-	JMP I FIXY
-	CLA
-	TAD [1000]
-	DCA INPUTY
-	JMP I FIXY
-
-/ Wrap INPUTO pointer at 2000 back to 1000
-FIXO,	0
-	TAD INPUTO
-	TAD [-2000]
-	SZA
-	JMP I FIXO
-	CLA
-	TAD [1000]
-	DCA INPUTO
-	JMP I FIXO
-
-*300
-
-SAVED,	0
-- 
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