diff --git a/src/chipset/stpc.c b/src/chipset/stpc.c
index 6d5177be8..30a4ab988 100644
--- a/src/chipset/stpc.c
+++ b/src/chipset/stpc.c
@@ -626,9 +626,9 @@ stpc_reg_write(uint16_t addr, uint8_t val, void *priv)
 			break;
 
 		case 0x52: case 0x53: case 0x54: case 0x55:
-			stpc_log("STPC: Set IRQ routing: INT %c -> %d\n", 0x41 + ((dev->reg_offset & 0x03) ^ 0x02), (val & 0x80) ? (val & 0xf) : -1);
+			stpc_log("STPC: Set IRQ routing: INT %c -> %d\n", 0x41 + (dev->reg_offset & 0x03), (val & 0x80) ? (val & 0xf) : -1);
 			val &= 0x8f;
-			pci_set_irq_routing(PCI_INTA + ((dev->reg_offset & 0x03) ^ 0x02), (val & 0x80) ? (val & 0xf) : PCI_IRQ_DISABLED);
+			pci_set_irq_routing(PCI_INTA + (dev->reg_offset & 0x03), (val & 0x80) ? (val & 0xf) : PCI_IRQ_DISABLED);
 			break;
 
 		case 0x56: case 0x57:
diff --git a/src/include/86box/vid_voodoo_codegen_x86-64.h b/src/include/86box/vid_voodoo_codegen_x86-64.h
index cecf3a539..f684176aa 100644
--- a/src/include/86box/vid_voodoo_codegen_x86-64.h
+++ b/src/include/86box/vid_voodoo_codegen_x86-64.h
@@ -41,7 +41,8 @@ static int last_block[2] = {0, 0};
 static int next_block_to_write[2] = {0, 0};
 
 #define addbyte(val)                                    \
-        code_block[block_pos++] = val;                  \
+        if (block_pos < BLOCK_SIZE)                     \
+                code_block[block_pos++] = val;          \
         if (block_pos >= BLOCK_SIZE)                    \
                 fatal("Over!\n")
 
diff --git a/src/include/86box/vid_voodoo_codegen_x86.h b/src/include/86box/vid_voodoo_codegen_x86.h
index 6cf2562d0..15c9951c1 100644
--- a/src/include/86box/vid_voodoo_codegen_x86.h
+++ b/src/include/86box/vid_voodoo_codegen_x86.h
@@ -39,7 +39,8 @@ static int last_block[2] = {0, 0};
 static int next_block_to_write[2] = {0, 0};
 
 #define addbyte(val)                                    \
-        code_block[block_pos++] = val;                  \
+        if (block_pos < BLOCK_SIZE)                     \
+                code_block[block_pos++] = val;          \
         if (block_pos >= BLOCK_SIZE)                    \
                 fatal("Over!\n")