From f8c9564372709e0634c9eb0c208ec9cc31a93de7 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Tue, 25 Dec 2018 01:54:02 +0100
Subject: Add if construct; fib example

---
 sjit_c.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

(limited to 'sjit_c.c')

diff --git a/sjit_c.c b/sjit_c.c
index 879ec18..325de47 100644
--- a/sjit_c.c
+++ b/sjit_c.c
@@ -11,6 +11,8 @@ enum instr {
 	Pop,
 
 	Call,
+	Jmp,
+	JmpTrue,
 	Ret,
 	Halt,
 
@@ -28,6 +30,8 @@ static inline uint32_t instr_size(enum instr instr) {
 		case Pop:     return 4;
 
 		case Call:    return 5;
+		case Jmp:     return 5;
+		case JmpTrue: return 1+3+6;
 		case Ret:     return 1;
 		case Halt:    return 1+1;
 
@@ -52,7 +56,7 @@ static inline void gen_instr(char *full_code, char **code_p, uint64_t **pgm_p, u
 		case PushRef:
 			arg=pgm[1];
 #ifdef DEBUG_JIT_INSTRUCTIONS
-			fprintf(stderr,"PushRef %lu\n",arg);
+			fprintf(stderr,"PushRef %ld\n",arg);
 #endif
 			code[0]='\x48'; /* mov rcx,[rsp+ARG*8] */
 			code[1]='\x8b';
@@ -86,7 +90,7 @@ static inline void gen_instr(char *full_code, char **code_p, uint64_t **pgm_p, u
 			code[2]='\x89';
 			code[3]='\x4c';
 			code[4]='\x24';
-			code[5]=(unsigned char)(arg-1)*8;
+			code[5]=(unsigned char)arg*8;
 			pgm+=2;
 			code+=6;
 			break;
@@ -113,6 +117,31 @@ static inline void gen_instr(char *full_code, char **code_p, uint64_t **pgm_p, u
 			pgm+=2;
 			code+=5;
 			break;
+		case Jmp:
+			arg=pgm[1];
+#ifdef DEBUG_JIT_INSTRUCTIONS
+			fprintf(stderr,"Jmp %lu -> %d\n",arg,mapping[arg]-(uint32_t)(&code[5]-full_code));
+#endif
+			code[0]='\xe9'; /* jmpq ARG */
+			*(uint32_t*)&code[1]=mapping[arg]-(&code[5]-full_code);
+			pgm+=2;
+			code+=5;
+			break;
+		case JmpTrue:
+			arg=pgm[1];
+#ifdef DEBUG_JIT_INSTRUCTIONS
+			fprintf(stderr,"JmpTrue %lu -> %d\n",arg,mapping[arg]-(uint32_t)(&code[10]-full_code));
+#endif
+			code[0]='\x59'; /* pop rcx */
+			code[1]='\x48'; /* test rcx,rcx */
+			code[2]='\x85';
+			code[3]='\xc9';
+			code[4]='\x0f'; /* jne ARG */
+			code[5]='\x85';
+			*(uint32_t*)&code[6]=mapping[arg]-(&code[10]-full_code);
+			pgm+=2;
+			code+=10;
+			break;
 		case Ret:
 #ifdef DEBUG_JIT_INSTRUCTIONS
 			fprintf(stderr,"Ret\n");
@@ -206,6 +235,8 @@ char *jit_append(char *code_block, uint32_t code_len, char *code_ptr,
 			case Put:
 			case Pop:
 			case Call:
+			case Jmp:
+			case JmpTrue:
 				pgm_p+=2;
 				break;
 			default:
-- 
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