restructure: get rid of cpu/utility

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>
2023-09-23 14:12:53 +05:30
parent 1e8966553f
commit 6c33c77ef3
12 changed files with 197 additions and 191 deletions
--- a/src/cpu/alu.cc
+++ b/src/cpu/alu.cc
@@ -0,0 +1,71 @@
+#include "alu.hh"
+#include "util/bits.hh"
+
+namespace matar {
+uint32_t
+eval_shift(ShiftType shift_type, uint32_t value, uint8_t amount, bool& carry) {
+    uint32_t eval = 0;
+
+    switch (shift_type) {
+        case ShiftType::LSL:
+
+            if (amount > 0 && amount <= 32)
+                carry = get_bit(value, 32 - amount);
+            else if (amount > 32)
+                carry = 0;
+
+            eval = value << amount;
+            break;
+        case ShiftType::LSR:
+
+            if (amount > 0 && amount <= 32)
+                carry = get_bit(value, amount - 1);
+            else if (amount > 32)
+                carry = 0;
+            else
+                carry = get_bit(value, 31);
+
+            eval = value >> amount;
+            break;
+        case ShiftType::ASR:
+            if (amount > 0 && amount <= 32)
+                carry = get_bit(value, amount - 1);
+            else
+                carry = get_bit(value, 31);
+
+            return static_cast<int32_t>(value) >> amount;
+            break;
+        case ShiftType::ROR:
+            if (amount == 0) {
+                eval  = (value >> 1) | (carry << 31);
+                carry = get_bit(value, 0);
+            } else {
+                eval  = std::rotr(value, amount);
+                carry = get_bit(value, (amount % 32 + 31) % 32);
+            }
+            break;
+    }
+
+    return eval;
+}
+
+std::ostream&
+operator<<(std::ostream& os, const ShiftType shift_type) {
+
+#define CASE(type)                                                             \
+    case ShiftType::type:                                                      \
+        os << #type;                                                           \
+        break;
+
+    switch (shift_type) {
+        CASE(LSL)
+        CASE(LSR)
+        CASE(ASR)
+        CASE(ROR)
+    }
+
+#undef CASE
+
+    return os;
+}
+}