From ac48d2c6b737417d2765a4b13a9d036bad4f46bd Mon Sep 17 00:00:00 2001
From: lux <michael.krause@uni-leipzig.de>
Date: Thu, 17 Aug 2017 15:28:30 +0200
Subject: [PATCH] Comment code in the main-function

---
 src/main.c | 25 ++++++++++++++-----------
 src/toy.c  |  7 +++----
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/main.c b/src/main.c
index abd65f1..c65f215 100644
--- a/src/main.c
+++ b/src/main.c
@@ -11,24 +11,26 @@
 int main(int argc, char *argv[])
 {
     uint16_t    ram[RAM_SIZE];
-    uint16_t    ir=0;
-    uint8_t     op_code;
-    uint16_t    pc = 0;
-    int         data_addr=0;
-    int         quit='n';
-    bool        run = true;
+    uint16_t    ir=0;           //Instruction Register
+    uint8_t     op_code;        //CPU Operation Code
+    uint16_t    pc = 0;         //Program Counter
+    int         data_addr=0;    //Adress of the 2nd operator (1. is ACCU)
+    int         quit='n';       //Helper for program-flow exit (not part of CPU)
+    bool        run = true;     //CPU halt and reset.(make better a coredamp befor)
 
     printf("\n+++++++++++++++++++++++++++++++++++++++++++++++\n+Boot: "CPU_TYPE
     " wite %zu x %zu Bit RAM.+\n+++++++++++++++++++++++++++++++++++++++++++++++\n\n"
     ,(sizeof(ram)/sizeof(ram[0])),sizeof(ram[0])*8);
     
-    if(initialise_ram(ram,argc,argv)==-1) return 1;
+    if(initialise_ram(ram,argc,argv)==-1) return 1; //load data from command line into RAM
+                                                    //(-1 in case of error, 
+                                                    //else number of correct read worts)
 
     while(run && pc<(RAM_SIZE-1))
     {
-        ir = ram[pc];
-        op_code = get_opcode(ir);
-        data_addr=find_data(ir);
+        ir = ram[pc];                       //get instruction from RAM
+        op_code = get_opcode(ir);           //determine the instruction form
+        data_addr=find_data(ir);            //locate the 2nd operand (ignord from OP_Code 8 to 15)
 
         //Handele user output
         printf("\ninstruction: ");
@@ -36,8 +38,9 @@ int main(int argc, char *argv[])
         printf("OP Code: %"PRIu8"\t",op_code);
         printf("Adresse: %u\n",data_addr);
         printf("\ninstruction result:\n");
+
         //CPU control flow
-        if(execute(op_code,data_addr,ram)) //jump if ALU says 
+        if(execute(op_code,data_addr,ram))  //EXECUTE instruction, jump if ALU says 
             pc=find_data(ram[pc]); 
         else pc++;
 
diff --git a/src/toy.c b/src/toy.c
index 1ae9bcb..d1b91a6 100644
--- a/src/toy.c
+++ b/src/toy.c
@@ -13,7 +13,8 @@ int initialise_ram(uint16_t *ram, int argc, char **argv )
 
     if(argc<2) 
     {
-        fprintf(stderr,"%s","no \".toy\" input file!\n");
+        fprintf(stderr,"%s","no \".toy\" input file!\n" 
+                "interpretation terminated.\n");
         return -1;
     }
     if(argc >2)
@@ -79,9 +80,7 @@ int get2compl(uint16_t value)
 
 bool execute(uint8_t op_code, int data_addr, uint16_t *ram) // jump when 1
 {
-
-    //vorsicht uint16 und Zweierkomplement noch nicht stringent !!!
-    //Vorsicht bool ops bei sigend int typs sind undefiniert !
+    //Vorsicht: bool ops bei sigend int typs sind nach c99 undefiniert !
    static uint16_t accu;
    bool jump=false;