diff --git a/H/Regs.h b/H/Regs.h
index d51a155b0..adf6ff594 100644
--- a/H/Regs.h
+++ b/H/Regs.h
@@ -31,12 +31,12 @@
 #undef  PUSH_X
 #endif
 
-#ifdef __x86_64__
-#undef  PUSH_REGS
+#ifdef sparc
+#define PUSH_REGS 1
 #undef  PUSH_X
 #endif
 
-#if defined(sparc) || defined(__sparc)
+#ifdef __x86_64__
 #undef  PUSH_REGS
 #undef  PUSH_X
 #endif
@@ -202,66 +202,7 @@ extern int Yap_stack_overflows;
 #define YENV_ADDRESS (&(YENV))
 #define MEM2YENV  
 
-#if defined(__GNUC__) && defined(sparc) && !defined(__NetBSD__) && !defined(THREADS)
-
-#define P    Yap_REGS.P_		/* prolog machine program counter         */
-#define YENV Yap_REGS.YENV_	/* current environment (may differ from   ENV)*/
-#define S    Yap_REGS.S_		/* structure pointer                      */
-
-register CELL *H asm ("g5");
-#define TR         Yap_REGS.TR_	/* latest choice point            */
-#define  B         Yap_REGS.B_	/* latest choice point            */
-#define CP         Yap_REGS.CP_	/* continuation   program counter         */
-#define HB         Yap_REGS.HB_	/* heap (global) stack top at time of latest c.p. */
-#define CreepFlag  Yap_REGS.CreepFlag_
-
-EXTERN inline void save_machine_regs(void) {
-  Yap_REGS.H_   = H;
-}
-
-EXTERN inline void restore_machine_regs(void) {
-  H = Yap_REGS.H_;
-}
-
-#define BACKUP_MACHINE_REGS()           \
-  CELL     *BK_H = H;                   \
-  restore_machine_regs()
-
-#define RECOVER_MACHINE_REGS()          \
-  save_machine_regs();                  \
-  H = BK_H
-
-EXTERN inline void save_H(void) {
-  Yap_REGS.H_   = H;
-}
-
-EXTERN inline void restore_H(void) {
-  H = Yap_REGS.H_;
-}
-
-#define BACKUP_H()  CELL *BK_H = H;  restore_H()
-
-#define RECOVER_H()   save_H(); H = BK_H
-
-EXTERN inline void save_B(void) {
-}
-
-EXTERN inline void restore_B(void) {
-}
-
-#if defined(__svr4__)
-#define BACKUP_B()
-
-#define RECOVER_B()
-#else
-#define BACKUP_B()  
-
-#define RECOVER_B()   
-#endif
-
-#define restore_TR() 
-
-#elif defined(__GNUC__) && defined(__alpha)
+#if defined(__GNUC__) && defined(__alpha)
 
 #define P               Yap_REGS.P_	/* prolog machine program counter */
 #define YENV            Yap_REGS.YENV_	/* current environment (may differ from ENV) */
diff --git a/H/absmi.h b/H/absmi.h
index 5aee6e98f..ce9423edb 100644
--- a/H/absmi.h
+++ b/H/absmi.h
@@ -36,16 +36,6 @@ static char SccsId[] = "%W% %G%";
  */
 #ifdef __GNUC__
 
-#if defined(sparc) || defined(__sparc)
-#define SHADOW_P       1
-#define SHADOW_Y       1
-#define SHADOW_S       1
-#define SHADOW_REGS    1
-#define SHADOW_CP      1
-#define SHADOW_HB      1
-#define USE_PREFETCH   1
-#endif
-
 #ifdef hppa
 #define SHADOW_P       1
 #define SHADOW_Y       1
@@ -91,6 +81,16 @@ register struct yami* P1REG asm ("bp"); /* can't use yamop before Yap.h */
 #endif /* BP_FREE */
 #endif /* i386 */
 
+#ifdef sparc
+#define SHADOW_P       1
+#ifdef BP_FREE
+#undef BP_FREE
+#endif
+#define S_IN_MEM       1
+#define      Y_IN_MEM  1
+#define     TR_IN_MEM  1
+#endif /* sparc_ */
+
 #ifdef __x86_64__
 #define SHADOW_P       1
 #ifdef BP_FREE