From 976f37c0bcb861ec03d721c7900b14b3bd47cdad Mon Sep 17 00:00:00 2001
From: folkert van heusden <mail@vanheusden.com>
Date: Wed, 16 Mar 2022 21:05:15 +0100
Subject: [PATCH] SXT was not implemented

---
 cpu.cpp | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/cpu.cpp b/cpu.cpp
index 40cabe6..5e68376 100644
--- a/cpu.cpp
+++ b/cpu.cpp
@@ -854,8 +854,24 @@ bool cpu::single_operand_instructions(const uint16_t instr)
 				  psw = getGAM(dst_mode, dst_reg, word_mode, false, src_gam_text);
 				  break;
 
-		case 0b000110111: // MFPS (get PSW to something)
-				  putGAM(dst_mode, dst_reg, word_mode, psw, false, dst_gam_text);
+		case 0b000110111: // MFPS (get PSW to something) / SXT
+				  if (word_mode) {  // MFPS
+				  	putGAM(dst_mode, dst_reg, word_mode, psw, false, dst_gam_text);
+				  }
+				  else {  // SXT
+					a = getGAMAddress(dst_mode, dst_reg, word_mode, false);
+					v = b -> read(a, word_mode);
+
+					vl = getPSW_n() ? -1 : 0;
+
+					setPSW_z(getPSW_n() == false);
+					setPSW_v(false);
+
+					if (dst_mode == 0)
+						putGAM(dst_mode, dst_reg, word_mode, vl, false, dst_gam_text);
+					else
+						b -> write(a, word_mode, vl);
+				  }
 				  break;
 
 		default: