diff --git a/src/cpu/rsp.c b/src/cpu/rsp.c
index e570d78a..68919465 100644
--- a/src/cpu/rsp.c
+++ b/src/cpu/rsp.c
@@ -9,10 +9,10 @@ rsp_t n64rsp;
 
 bool rsp_acquire_semaphore() {
     if (N64RSP.semaphore_held) {
-        return false; // Semaphore is already held
+        return true; // Semaphore is already held
     } else {
         N64RSP.semaphore_held = true;
-        return true; // Acquired semaphore.
+        return false; // Acquired semaphore.
     }
 }
 
diff --git a/src/cpu/rsp_interface.c b/src/cpu/rsp_interface.c
index 4b67f0b6..2c88e915 100644
--- a/src/cpu/rsp_interface.c
+++ b/src/cpu/rsp_interface.c
@@ -87,7 +87,7 @@ word read_word_spreg(word address) {
         case ADDR_SP_DMA_BUSY_REG:
             return 0; // DMA not busy, since it's instant.
         case ADDR_SP_SEMAPHORE_REG:
-            return N64RSP.semaphore_held;
+            return rsp_acquire_semaphore();
         default:
             logfatal("Reading word from unknown/unsupported address 0x%08X in region: REGION_SP_REGS", address);
     }
@@ -119,11 +119,7 @@ void write_word_spreg(word address, word value) {
         case ADDR_SP_DMA_BUSY_REG:
             logfatal("Write to unsupported SP reg: ADDR_SP_DMA_BUSY_REG");
         case ADDR_SP_SEMAPHORE_REG:
-            if (value == 0) {
-                rsp_release_semaphore();
-            } else {
-                logfatal("Wrote non-zero value 0x%08X to SP reg ADDR_SP_SEMAPHORE_REG", value);
-            }
+            rsp_release_semaphore();
         case ADDR_SP_PC_REG:
             set_rsp_pc(value);
             break;