From 9cf92379d5fcf0076c25dae0935daab446c992cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= <cynerd@email.cz>
Date: Wed, 30 Aug 2017 21:37:53 +0200
Subject: Initial commit

Adding work done so far.
---
 qtmips_machine/registers.cpp | 66 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 qtmips_machine/registers.cpp

(limited to 'qtmips_machine/registers.cpp')

diff --git a/qtmips_machine/registers.cpp b/qtmips_machine/registers.cpp
new file mode 100644
index 0000000..514987a
--- /dev/null
+++ b/qtmips_machine/registers.cpp
@@ -0,0 +1,66 @@
+#include "registers.h"
+#include "qtmipsexception.h"
+#include "utils.h"
+
+// TODO should this be configurable?
+//////////////////////////////////////////////////////////////////////////////
+/// Program counter initial value
+#define PC_INIT 0x80020000
+//////////////////////////////////////////////////////////////////////////////
+
+Registers::Registers() {
+    this->pc = PC_INIT; // Initialize to beginning program section
+    for (int i = 0; i < 31; i++)
+        this->gp[i] = 0;
+    this->hi = this->lo = 0;
+}
+
+std::uint32_t Registers::read_pc() {
+    return this->pc;
+}
+
+std::uint32_t Registers::pc_inc() {
+    this->pc += 4;
+    return this->pc;
+}
+
+std::uint32_t Registers::pc_jmp(std::int32_t offset) {
+    if (offset % 4)
+        throw QTMIPS_EXCEPTION(UnalignedJump, "Trying to jump by unaligned offset", to_string_hex(offset));
+    this->pc += offset;
+    return this->pc;
+}
+
+void Registers::pc_abs_jmp(std::uint32_t address) {
+    if (address % 4)
+        throw QTMIPS_EXCEPTION(UnalignedJump, "Trying to jump to unaligned address", to_string_hex(address));
+    this->pc = address;
+}
+
+std::uint32_t Registers::read_gp(std::uint8_t i) {
+    SANITY_ASSERT(i < 32, std::string("Trying to read from register ") + std::to_string(i));
+    if (!i) // $0 always reads as 0
+        return 0;
+    return this->gp[i - 1];
+}
+
+void Registers::write_gp(std::uint8_t i, std::uint32_t value) {
+    SANITY_ASSERT(i < 32, std::string("Trying to write to register ") + std::to_string(i));
+    if (i == 0) // Skip write to $0
+        return;
+    this->gp[i - 1] = value;
+}
+
+std::uint32_t Registers::read_hi_lo(bool hi) {
+    if (hi)
+        return this->hi;
+    else
+        return this->lo;
+}
+
+void Registers::write_hi_lo(bool hi, std::uint32_t value) {
+    if (hi)
+        this->hi = value;
+    else
+        this->lo = value;
+}
-- 
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