--- hatari/src/falcon/dsp_cpu.c	2019/04/09 08:51:18	1.1.1.7
+++ hatari/src/falcon/dsp_cpu.c	2019/04/09 08:52:11	1.1.1.8
@@ -705,11 +705,11 @@ void dsp56k_init_cpu(void)
 /**
  * Execute one instruction in trace mode at a given PC address.
  * */
-Uint32 dsp56k_execute_one_disasm_instruction(Uint32 pc)
+Uint16 dsp56k_execute_one_disasm_instruction(Uint16 pc)
 {
 	dsp_core_t *ptr1, *ptr2;
 	static dsp_core_t dsp_core_save;
-	Uint32 instruction_length;
+	Uint16 instruction_length;
 
 	ptr1 = &dsp_core;
 	ptr2 = &dsp_core_save;
@@ -1387,14 +1387,16 @@ static void dsp_write_reg(Uint32 numreg,
 			dsp_core.registers[DSP_REG_SR] = value & 0xaf7f;
 			break;
 		case DSP_REG_SP:
-			stack_error = dsp_core.registers[DSP_REG_SP] & (1<<DSP_SP_SE);
-			if ((stack_error==0) && (value & (1<<DSP_SP_SE))) {
-				/* Stack full, raise interrupt */
+			stack_error = dsp_core.registers[DSP_REG_SP] & (3<<DSP_SP_SE);
+			if ((stack_error==0) && (value & (3<<DSP_SP_SE))) {
+				/* Stack underflow or overflow detected, raise interrupt */
 				dsp_add_interrupt(DSP_INTER_STACK_ERROR);
 				if (!isDsp_in_disasm_mode)
-					fprintf(stderr,"Dsp: Stack Overflow\n");
+					fprintf(stderr,"Dsp: Stack Overflow or Underflow\n");
+				dsp_core.registers[DSP_REG_SP] = value & (3<<DSP_SP_SE);
 			}
-			dsp_core.registers[DSP_REG_SP] = value & BITMASK(6); 
+			else
+				dsp_core.registers[DSP_REG_SP] = value & BITMASK(6); 
 			dsp_compute_ssh_ssl();
 			break;
 		case DSP_REG_SSH: