diff --git a/cpu.cpp b/cpu.cpp
index 1d0437c..3370a25 100644
--- a/cpu.cpp
+++ b/cpu.cpp
@@ -498,14 +498,16 @@ gam_rc_t cpu::getGAM(const uint8_t mode, const uint8_t reg, const word_mode_t wo
 			g.addr  = b->read(get_register(reg), wm_word, rm_cur, isR7_space);
 			// might be wrong: the adds should happen when the read is really performed, because of traps
 			add_register(reg, 2);
-			g.mmr1_update = { 2, reg };
+			if (reg != 7)
+				g.mmr1_update = { 2, reg };
 			g.space = d_space;
 			if (read_value)
 				g.value = b->read(g.addr.value(), word_mode, rm_cur, g.space);
 			break;
 		case 4:  // -(Rn)
 			add_register(reg, word_mode == wm_word || reg == 7 || reg == 6 ? -2 : -1);
-			g.mmr1_update = { word_mode == wm_word || reg == 7 || reg == 6 ? -2 : -1, reg };
+			if (reg != 7)
+				g.mmr1_update = { word_mode == wm_word || reg == 6 ? -2 : -1, reg };
 			g.space = d_space;
 			g.addr  = get_register(reg);
 			if (read_value)
@@ -513,7 +515,8 @@ gam_rc_t cpu::getGAM(const uint8_t mode, const uint8_t reg, const word_mode_t wo
 			break;
 		case 5:  // @-(Rn)
 			add_register(reg, -2);
-			g.mmr1_update = { -2, reg };
+			if (reg != 7)
+				g.mmr1_update = { -2, reg };
 			g.addr  = b->read(get_register(reg), wm_word, rm_cur, isR7_space);
 			g.space = d_space;
 			if (read_value)