emux64: cpu: Seperate arithop core from add logic

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 44 insertions, 4 deletions

diff --git a/emux64/src/cpu/cpu_cycle.c b/emux64/src/cpu/cpu_cycle.c
index cdbf87f..b3a8987 100644
--- a/emux64/src/cpu/cpu_cycle.c
+++ b/emux64/src/cpu/cpu_cycle.c
@@ -34,6 +34,19 @@
 #include "cpu/cpu.h"
 
 /*
+ * Represents arithmetic arguments
+ *
+ * @dest_reg: Destination register [R]
+ * @op1: Operand 1 [IMM]
+ * op2: Operand 2 [IMM]
+ */
+struct arithop {
+    uint8_t dest_reg;
+    uint64_t op1;
+    uint64_t op2;
+};
+
+/*
  * Returns true if the register is an
  * X<n> type register
  *
@@ -112,16 +125,27 @@ cpu_fetch32(struct osmx_core *core, uint64_t *res)
     return 0;
 }
 
+/*
+ * Get arithmetic parameters
+ *
+ * @core: Core that is executing
+ * @res: Result written here
+ *
+ * Returns zero on success
+ */
 static int
-cpu_do_add(struct osmx_core *core)
+cpu_arithop(struct osmx_core *core, struct arithop *res)
 {
     uint8_t dest, op1, op2;
-    uint64_t op1_val;
     uint64_t op2_val;
     bool op2_is_imm;
     bool op2_is_big;
     int error = 0;
 
+    if (core == NULL || res == NULL) {
+        return -EINVAL;
+    }
+
     /* Grab the dest register */
     error = cpu_fetch(core, &dest);
     if (error < 0) {
@@ -161,8 +185,24 @@ cpu_do_add(struct osmx_core *core)
         return error;
     }
 
-    op1_val = core->xn[op1];
-    core->xn[dest] = op1_val + op2_val;
+    res->dest_reg = dest;
+    res->op1 = core->xn[op1];
+    res->op2 = op2_val;
+    return 0;
+}
+
+static int
+cpu_do_add(struct osmx_core *core)
+{
+    struct arithop ops;
+    int error;
+
+    error = cpu_arithop(core, &ops);
+    if (error < 0) {
+        return error;
+    }
+
+    core->xn[ops.dest_reg] = ops.op1 + ops.op2;
     return 0;
 
 }