From 35588a07c841d7492349c92a24d5747388073f0a Mon Sep 17 00:00:00 2001
From: "(Tim) Efthimis Kritikos" <efkf@firemail.cc>
Date: Wed, 14 Feb 2024 14:03:03 +0000
Subject: [PATCH] CPU: Added support for reading into registers from indirect
 memory access with register

---
 assembly.c | 40 ++++++++++++++++++++++++++++++++++++++++
 cpu.c      | 28 ++++++++++++++++++----------
 test.asm   |  4 ++++
 3 files changed, 62 insertions(+), 10 deletions(-)

diff --git a/assembly.c b/assembly.c
index 30cfc50..f6aead6 100644
--- a/assembly.c
+++ b/assembly.c
@@ -456,6 +456,46 @@ int64_t assemble_line(char *line, struct assembler_context_t *assembler_context)
 						return -2;
 				}else
 					return -2;
+			}else if(line[x]=='('){
+				while(line[x]==' ')x++;
+				x++;
+				if(line[x]=='%'){
+					x++;
+					if(line[x]=='R'){
+						x++;
+						if(line[x]>='0'&&line[x]<='7'){
+							r0=line[x]-'0';
+							x++;
+							while(line[x]==' ')x++;
+							if(line[x]==')'){
+								x++;
+								while(line[x]==' ')x++;
+								if(line[x]==','){
+									x++;
+									while(line[x]==' ')x++;
+									if(line[x]=='%'){
+										x++;
+										if(line[x]=='R'){
+											x++;
+											if(line[x]>='0'&&line[x]<='7'){
+												r1=line[x]-'0';
+												return 0x20090000|(r0&0xFF)<<8|(r1&0xFF);
+											}else
+												return -2;
+										}else
+											return -2;
+									}else
+										return -2;
+								}else
+									return -2;
+							}else
+								return -2;
+						}else
+							return -2;
+					}else
+						return -2;
+				}else
+					return -2;
 			}else
 				return -2;
 		}else if(strncmp(line,"HALT ",5)==0||strncmp(line,"HALT\0",5)==0){
diff --git a/cpu.c b/cpu.c
index f64494a..2213520 100644
--- a/cpu.c
+++ b/cpu.c
@@ -59,12 +59,12 @@ int decode(struct simdata_t *simdata){
 					simdata->exec_data->out_op->data=simdata->decode_data->in_bytecode&0x00FFFFFF;
 					simdata->exec_data->EXEC_ACTION=(opcode&0x10)?CALL:JUMP;
 					break;
-				case 0x0F:
+				case 0x0F:/* load SP */
 					simdata->exec_data->EXEC_ACTION=MOVE;
 					simdata->exec_data->in_op1->OP_ADDR=IMMEDIATE;
 					simdata->exec_data->in_op1->data=simdata->decode_data->in_bytecode&0x00FFFFFF;
 					simdata->exec_data->out_op->OP_ADDR=REGISTER;
-					simdata->exec_data->out_op->data=0;
+					simdata->exec_data->out_op->data=0xFF;
 					break;
 				case 0x10:
 					simdata->exec_data->EXEC_ACTION=RET;
@@ -311,17 +311,25 @@ int exec(struct simdata_t *simdata){
 							simdata->registers->GPR[simdata->exec_data->in_op1->data])<<16);
 					break;
 				case REGISTER: /* This is for special registers like the SP which is 24bits long */
-					if(simdata->exec_data->in_op1->OP_ADDR==IMMEDIATE){
-						if( (simdata->exec_data->in_op1->data&0xFF000000) == 0 )
-							simdata->registers->SP=simdata->exec_data->in_op1->data;
-						else
-							return 2;
-					}else{
+					if(simdata->exec_data->out_op->data==0xFF){
+						if(simdata->exec_data->in_op1->OP_ADDR==IMMEDIATE){
+							if( (simdata->exec_data->in_op1->data&0xFF000000) == 0 )
+								simdata->registers->SP=simdata->exec_data->in_op1->data;
+							else
+								return 2;
+						}else if( simdata->exec_data->in_op1->OP_ADDR==REGISTER ){ /*for completeion, not valid ( yet )*/
+							if( (simdata->registers->GPR[simdata->exec_data->in_op1->data]&0xFF000000) == 0 )
+								simdata->registers->SP=simdata->registers->GPR[simdata->exec_data->in_op1->data];
+							else
+								return 2;
+						}
+					}else if(simdata->exec_data->in_op1->OP_ADDR==REGISTER_IND){
 						if( (simdata->registers->GPR[simdata->exec_data->in_op1->data]&0xFF000000) == 0 )
-							simdata->registers->SP=simdata->registers->GPR[simdata->exec_data->in_op1->data];
+							simdata->registers->GPR[simdata->exec_data->out_op->data]=*(uint32_t*)(simdata->RAM+simdata->registers->GPR[simdata->exec_data->in_op1->data]);
 						else
 							return 2;
-					}
+					}else
+						return 1;
 					break;
 				case REGISTER_IND:
 					if(simdata->exec_data->in_op1->OP_ADDR==REGISTER){
diff --git a/test.asm b/test.asm
index ce71671..9ecbe6c 100644
--- a/test.asm
+++ b/test.asm
@@ -48,6 +48,10 @@ MOV %R1,(%R0)
 MOV $0xcccd,%R1l
 MOV $0x3f4c,%R1h
 MOV %R1,(%R0)
+MOV $0x00D0,%R0l
+MOV $0x0000,%R0h
+MOV %R1,(%R0)
+MOV (%R0),%R5
 HALT
 :TR_LOW
 DDW $0xDEADBEEF