From cd9e572b6523fac483ce1695ae1785fca075cc53 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= <cynerd@email.cz>
Date: Tue, 21 Nov 2017 22:01:52 +0100
Subject: Implement and test ADD

---
 qtmips_machine/core.cpp | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

(limited to 'qtmips_machine/core.cpp')

diff --git a/qtmips_machine/core.cpp b/qtmips_machine/core.cpp
index 1edcc97..a7c5d20 100644
--- a/qtmips_machine/core.cpp
+++ b/qtmips_machine/core.cpp
@@ -11,7 +11,7 @@
 
 // This is map from opcode to signals.
 static const struct DecodeMap dmap[]  = {
-    { .supported = true, .mem2reg = false, .memwrite = false, .alubimm = false, .regd = false, .regwrite = true, .branch = false }, // Alu operations and more
+    { .supported = true, .mem2reg = true, .memwrite = false, .alubimm = false, .regd = true, .regwrite = true, .branch = false }, // Alu operations
     // TODO These are just copies of first one
     { .supported = true, .mem2reg = false, .memwrite = false, .alubimm = false, .regd = false, .regwrite = false, .branch = true }, // Branch on alu operations
     { .supported = true, .mem2reg = false, .memwrite = false, .alubimm = false, .regd = true, .regwrite = true, .branch = false }, // J
@@ -97,8 +97,17 @@ struct Core::dtDecode Core::decode(struct dtFetch dt) {
     if (!dec.supported)
         // TODO message
         throw QTMIPS_EXCEPTION(UnsupportedInstruction, "", "");
-    enum AluOp d_alu = ALU_OP_SLL; // TODO decode for real
+
+    // Prepare alu operation
+    enum AluOp d_alu;
+    if (dt.inst.opcode() == 0) {
+        d_alu = (enum  AluOp)dt.inst.funct();
+    } else
+        // TODO can't we ignore this?
+        d_alu = ALU_OP_SLL; // Just set it to zero so we won't do something stupid like throw exception
+
     return {
+        .inst = dt.inst,
         .mem2reg = dec.mem2reg,
         .memwrite = dec.memwrite,
         .alubimm = dec.alubimm,
@@ -108,17 +117,17 @@ struct Core::dtDecode Core::decode(struct dtFetch dt) {
         .aluop = d_alu,
         .val_rs = regs->read_gp(dt.inst.rs()),
         .val_rt = regs->read_gp(dt.inst.rt()),
-        .val_sa = dt.inst.shamt(),
-        .val_immediate = dt.inst.immediate(),
     };
     // TODO on jump there should be delay slot. Does processor addes it or compiler. And do we care?
 }
 
 struct Core::dtExecute Core::execute(struct dtDecode dt) {
     // TODO signals
+
     return {
         .mem2reg = dt.mem2reg,
-        .val = alu_operate(dt.aluop, dt.val_rs, dt.val_rt, dt.val_sa)
+        .rwrite = dt.regd ? dt.inst.rd() : dt.inst.rt(),
+        .alu_val = alu_operate(dt.aluop, dt.val_rs, dt.val_rt, dt.inst.shamt()),
     };
 }
 
@@ -126,13 +135,14 @@ struct Core::dtMemory Core::memory(struct dtExecute dt) {
     // TODO signals
     return {
         .mem2reg = dt.mem2reg,
-        .val = dt.val,
+        .rwrite = dt.rwrite,
+        .alu_val = dt.alu_val,
     };
 }
 
 void Core::writeback(struct dtMemory dt) {
     if (dt.mem2reg) {
-
+        regs->write_gp(dt.rwrite, dt.alu_val);
     }
 }
 
-- 
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