1 files changed, 49 insertions, 15 deletions

diff --git a/src/core/arm/interpreter/armemu.cpp b/src/core/arm/interpreter/armemu.cpp
index 522f9a1dd..56040a4eb 100644
--- a/src/core/arm/interpreter/armemu.cpp
+++ b/src/core/arm/interpreter/armemu.cpp
@@ -5839,21 +5839,46 @@ L_stm_s_takeabort:
                 const s16 rm_lo = (state->Reg[rm_idx] & 0xFFFF);
                 const s16 rm_hi = ((state->Reg[rm_idx] >> 16) & 0xFFFF);
 
+                s32 lo_result;
+                s32 hi_result;
+
                 // SSUB16
                 if ((instr & 0xFF0) == 0xf70) {
-                    state->Reg[rd_idx] = ((rn_lo - rm_lo) & 0xFFFF) | (((rn_hi - rm_hi) & 0xFFFF) << 16);
+                    lo_result = (rn_lo - rm_lo);
+                    hi_result = (rn_hi - rm_hi);
                 }
                 // SADD16
                 else if ((instr & 0xFF0) == 0xf10) {
-                    state->Reg[rd_idx] = ((rn_lo + rm_lo) & 0xFFFF) | (((rn_hi + rm_hi) & 0xFFFF) << 16);
+                    lo_result = (rn_lo + rm_lo);
+                    hi_result = (rn_hi + rm_hi);
                 }
                 // SSAX
                 else if ((instr & 0xFF0) == 0xf50) {
-                    state->Reg[rd_idx] = ((rn_lo + rm_hi) & 0xFFFF) | (((rn_hi - rm_lo) & 0xFFFF) << 16);
+                    lo_result = (rn_lo + rm_hi);
+                    hi_result = (rn_hi - rm_lo);
                 }
                 // SASX
                 else {
-                    state->Reg[rd_idx] = ((rn_lo - rm_hi) & 0xFFFF) | (((rn_hi + rm_lo) & 0xFFFF) << 16);
+                    lo_result = (rn_lo - rm_hi);
+                    hi_result = (rn_hi + rm_lo);
+                }
+
+                state->Reg[rd_idx] = (lo_result & 0xFFFF) | ((hi_result & 0xFFFF) << 16);
+
+                if (lo_result >= 0) {
+                    state->Cpsr |= (1 << 16);
+                    state->Cpsr |= (1 << 17);
+                } else {
+                    state->Cpsr &= ~(1 << 16);
+                    state->Cpsr &= ~(1 << 17);
+                }
+
+                if (hi_result >= 0) {
+                    state->Cpsr |= (1 << 18);
+                    state->Cpsr |= (1 << 19);
+                } else {
+                    state->Cpsr &= ~(1 << 18);
+                    state->Cpsr &= ~(1 << 19);
                 }
                 return 1;
             } else {
@@ -6192,18 +6217,27 @@ L_stm_s_takeabort:
 					//ichfly
 					//USAT16
 				{
-					u8 tar = BITS(12, 15);
-					u8 src = BITS(0, 3);
-					u8 val = BITS(16, 19);
-					s16 a1 = (state->Reg[src]);
-					s16 a2 = (state->Reg[src] >> 0x10);
-					s16 max = 0xFFFF >> (16 - val);
-					if (max < a1) a1 = max;
-					if (max < a2) a2 = max;
-					u32 temp2 = ((u32)(a2)) << 0x10;
-					state->Reg[tar] = (a1 & 0xFFFF) | (temp2);
+					const u8 rd_idx = BITS(12, 15);
+					const u8 rn_idx = BITS(0, 3);
+					const u8 num_bits = BITS(16, 19);
+					const s16 max = 0xFFFF >> (16 - num_bits);
+					s16 rn_lo = (state->Reg[rn_idx]);
+					s16 rn_hi = (state->Reg[rn_idx] >> 16);
+					
+					if (max < rn_lo)
+						rn_lo = max;
+					else if (rn_lo < 0)
+						rn_lo = 0;
+
+					if (max < rn_hi)
+						rn_hi = max;
+					else if (rn_hi < 0)
+						rn_hi = 0;
+					
+					state->Reg[rd_idx] = (rn_lo & 0xFFFF) | ((rn_hi << 16) & 0xFFFF);
+					return 1;
 				}
-				return 1;
+
 				default:
 					break;
 			}