diff --git a/src/arch/x86/image/nbi.c b/src/arch/x86/image/nbi.c
index e3d9440e0..9bf666828 100644
--- a/src/arch/x86/image/nbi.c
+++ b/src/arch/x86/image/nbi.c
@@ -59,8 +59,8 @@ struct imgheader {
 #define NBI_LENGTH(len) ( NBI_NONVENDOR_LENGTH(len) + NBI_VENDOR_LENGTH(len) )
 
 /* Interpretation of the "flags" fields */
-#define	NBI_PROGRAM_RETURNS(flags)	( (flags) & ( 1 << 8 ) )
-#define	NBI_LINEAR_EXEC_ADDR(flags)	( (flags) & ( 1 << 31 ) )
+#define	NBI_PROGRAM_RETURNS(flags)	( (flags) & ( 1U << 8 ) )
+#define	NBI_LINEAR_EXEC_ADDR(flags)	( (flags) & ( 1U << 31 ) )
 
 /** NBI header length */
 #define NBI_HEADER_LENGTH	512
@@ -88,7 +88,7 @@ struct segheader {
 #define NBI_LOADADDR_AFTER		0x01
 #define NBI_LOADADDR_END		0x02
 #define NBI_LOADADDR_BEFORE		0x03
-#define NBI_LAST_SEGHEADER(flags)	( (flags) & ( 1 << 2 ) )
+#define NBI_LAST_SEGHEADER(flags)	( (flags) & ( 1U << 2 ) )
 
 /* Define a type for passing info to a loaded program */
 struct ebinfo {
diff --git a/src/core/ansicoldef.c b/src/core/ansicoldef.c
index 4555c4e36..c9f0e0c2b 100644
--- a/src/core/ansicoldef.c
+++ b/src/core/ansicoldef.c
@@ -43,7 +43,8 @@ FILE_SECBOOT ( PERMITTED );
  * @v rgb		24-bit RGB value (or ANSICOL_NO_RGB)
  * @ret ansicol		ANSI colour definition
  */
-#define ANSICOL_DEFINE( basic, rgb ) ( ( (basic) << 28 ) | (rgb) )
+#define ANSICOL_DEFINE( basic, rgb ) \
+	( ( ( ( unsigned int ) (basic) ) << 28 ) | (rgb) )
 
 /**
  * Extract basic colour from ANSI colour definition
diff --git a/src/core/memmap_settings.c b/src/core/memmap_settings.c
index f54de9150..19872ead4 100644
--- a/src/core/memmap_settings.c
+++ b/src/core/memmap_settings.c
@@ -59,7 +59,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  */
 #define MEMMAP_TAG( start, count, include_start, include_length,	\
 		    ignore, scale )					\
-	( ( (start) << 16 ) | ( ( (count) - 1 ) << 24 ) |		\
+	( ( (start) << 16 ) | ( ( (count) - 1U ) << 24 ) |		\
 	  ( (ignore) << 10 ) | ( (include_length) << 9 ) |		\
 	  ( (include_start) << 8 ) | (scale) )
 
diff --git a/src/crypto/des.c b/src/crypto/des.c
index 685c417bb..255d93c6c 100644
--- a/src/crypto/des.c
+++ b/src/crypto/des.c
@@ -216,12 +216,18 @@ struct des_generator {
 		       INV3, BIT3, INV2, BIT2, INV1, BIT1, INV0, BIT0 )	\
 	{								\
 		.permutation = (PERMUTATION),				\
-		.seed = ( ( (INV0) << 31 ) | ( (BIT0) << 28 ) |		\
-			  ( (INV1) << 27 ) | ( (BIT1) << 24 ) |		\
-			  ( (INV2) << 23 ) | ( (BIT2) << 20 ) |		\
-			  ( (INV3) << 19 ) | ( (BIT3) << 16 ) |		\
-			  ( (INV4) << 15 ) | ( (BIT4) << 12 ) |		\
-			  ( (INV5) << 11 ) | ( (BIT5) <<  8 ) |		\
+		.seed = ( ( ( ( unsigned int ) (INV0) ) << 31 ) |	\
+			  ( ( ( unsigned int ) (BIT0) ) << 28 ) |	\
+			  ( ( ( unsigned int ) (INV1) ) << 27 ) |	\
+			  ( ( ( unsigned int ) (BIT1) ) << 24 ) |	\
+			  ( ( ( unsigned int ) (INV2) ) << 23 ) |	\
+			  ( ( ( unsigned int ) (BIT2) ) << 20 ) |	\
+			  ( ( ( unsigned int ) (INV3) ) << 19 ) |	\
+			  ( ( ( unsigned int ) (BIT3) ) << 16 ) |	\
+			  ( ( ( unsigned int ) (INV4) ) << 15 ) |	\
+			  ( ( ( unsigned int ) (BIT4) ) << 12 ) |	\
+			  ( ( ( unsigned int ) (INV5) ) << 11 ) |	\
+			  ( ( ( unsigned int ) (BIT5) ) <<  8 ) |	\
 			  ( ( uint32_t ) sizeof (PERMUTATION) - 1 ) |	\
 			  (OFFSET) ),					\
 	}
diff --git a/src/drivers/bus/usb_settings.c b/src/drivers/bus/usb_settings.c
index e34c79126..f244883ae 100644
--- a/src/drivers/bus/usb_settings.c
+++ b/src/drivers/bus/usb_settings.c
@@ -78,7 +78,7 @@ static int usb_settings_fetch ( struct settings *settings __unused,
 	int rc;
 
 	/* Extract parameters from tag */
-	tag_direction = ( ( setting->tag & ( 1 << 31 ) ) ? +1 : -1 );
+	tag_direction = ( ( setting->tag & ( 1U << 31 ) ) ? +1 : -1 );
 	tag_busdev = ( ( setting->tag >> 16 ) & 0x7fff );
 	tag_offset = ( ( setting->tag >> 8 ) & 0xff );
 	tag_len = ( ( setting->tag >> 0 ) & 0xff );
diff --git a/src/drivers/infiniband/mlx_bitops.h b/src/drivers/infiniband/mlx_bitops.h
index b6ca9f633..0340d55f7 100644
--- a/src/drivers/infiniband/mlx_bitops.h
+++ b/src/drivers/infiniband/mlx_bitops.h
@@ -85,7 +85,8 @@ typedef unsigned char pseudo_bit_t;
  */
 
 #define MLX_ASSEMBLE_1( _structure_st, _index, _field, _value )		     \
-	( (_value) << MLX_DWORD_BIT_OFFSET ( _structure_st, _index, _field ) )
+	( ( ( unsigned int ) (_value) ) <<				     \
+	  MLX_DWORD_BIT_OFFSET ( _structure_st, _index, _field ) )
 
 #define MLX_ASSEMBLE_2( _structure_st, _index, _field, _value, ... )	     \
 	( MLX_ASSEMBLE_1 ( _structure_st, _index, _field, _value ) |	     \
diff --git a/src/drivers/net/intelx.h b/src/drivers/net/intelx.h
index d68f50082..386c5efa1 100644
--- a/src/drivers/net/intelx.h
+++ b/src/drivers/net/intelx.h
@@ -109,7 +109,7 @@ FILE_SECBOOT ( PERMITTED );
 #define INTELX_MAXFRS_MFS(len)	( (len) << 16 )	/**< Maximum frame size */
 #define INTELX_MAXFRS_MFS_DEFAULT \
 	INTELX_MAXFRS_MFS ( ETH_FRAME_LEN + 4 /* VLAN */ + 4 /* CRC */ )
-#define INTELX_MAXFRS_MFS_MASK	INTELX_MAXFRS_MFS ( 0xffff )
+#define INTELX_MAXFRS_MFS_MASK	INTELX_MAXFRS_MFS ( 0xffffU )
 
 /** Link Status Register */
 #define INTELX_LINKS 0x042a4UL
diff --git a/src/drivers/usb/xhci.c b/src/drivers/usb/xhci.c
index 110e15f4c..051e16388 100644
--- a/src/drivers/usb/xhci.c
+++ b/src/drivers/usb/xhci.c
@@ -2166,7 +2166,7 @@ static void xhci_configure_endpoint_input ( struct xhci_device *xhci,
 
 	/* Populate slot context */
 	slot_ctx = ( input + xhci_input_context_offset ( xhci, XHCI_CTX_SLOT ));
-	slot_ctx->info = cpu_to_le32 ( XHCI_SLOT_INFO ( ( XHCI_CTX_END - 1 ),
+	slot_ctx->info = cpu_to_le32 ( XHCI_SLOT_INFO ( ( XHCI_CTX_END - 1U ),
 							( slot->ports ? 1 : 0 ),
 							slot->psiv, 0 ) );
 	slot_ctx->ports = slot->ports;
@@ -2232,7 +2232,7 @@ xhci_deconfigure_endpoint_input ( struct xhci_device *xhci __unused,
 
 	/* Populate slot context */
 	slot_ctx = ( input + xhci_input_context_offset ( xhci, XHCI_CTX_SLOT ));
-	slot_ctx->info = cpu_to_le32 ( XHCI_SLOT_INFO ( ( XHCI_CTX_END - 1 ),
+	slot_ctx->info = cpu_to_le32 ( XHCI_SLOT_INFO ( ( XHCI_CTX_END - 1U ),
 							0, 0, 0 ) );
 }
 
@@ -2287,7 +2287,7 @@ static void xhci_evaluate_context_input ( struct xhci_device *xhci,
 
 	/* Populate slot context */
 	slot_ctx = ( input + xhci_input_context_offset ( xhci, XHCI_CTX_SLOT ));
-	slot_ctx->info = cpu_to_le32 ( XHCI_SLOT_INFO ( ( XHCI_CTX_END - 1 ),
+	slot_ctx->info = cpu_to_le32 ( XHCI_SLOT_INFO ( ( XHCI_CTX_END - 1U ),
 							0, 0, 0 ) );
 
 	/* Populate endpoint context */
diff --git a/src/include/curses.h b/src/include/curses.h
index bbc437a4e..16a5a3af3 100644
--- a/src/include/curses.h
+++ b/src/include/curses.h
@@ -144,7 +144,7 @@ extern WINDOW _stdscr;
 #define A_STANDOUT	WA_STANDOUT
 #define A_UNDERLINE	WA_UNDERLINE
 
-#define A_ATTRIBUTES	( 0xffff << ATTRS_SHIFT )
+#define A_ATTRIBUTES	( 0xffffU << ATTRS_SHIFT )
 #define A_CHARTEXT	( 0xff )
 #define A_COLOUR	( 0xff << CPAIR_SHIFT )
 #define A_COLOR		A_COLOUR
diff --git a/src/include/ipxe/xsigo.h b/src/include/ipxe/xsigo.h
index f4f14c487..05bb4042a 100644
--- a/src/include/ipxe/xsigo.h
+++ b/src/include/ipxe/xsigo.h
@@ -37,9 +37,9 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 /** Xsigo resource types */
 enum xsigo_resource_type {
 	/** Virtual Ethernet resource type */
-	XSIGO_RESOURCE_XVE = ( 1 << 6 ),
+	XSIGO_RESOURCE_XVE = ( 1U << 6 ),
 	/** Absence-of-high-availability "resource" type */
-	XSIGO_RESOURCE_NO_HA = ( 1 << 4 ),
+	XSIGO_RESOURCE_NO_HA = ( 1U << 4 ),
 };
 
 /** A Xsigo server identifier */
@@ -216,7 +216,7 @@ enum xsmp_session_type {
 /** XSMP boot flags */
 enum xsmp_session_boot {
 	/** PXE boot */
-	XSMP_BOOT_PXE = ( 1 << 0 ),
+	XSMP_BOOT_PXE = ( 1U << 0 ),
 };
 
 /** XSMP virtual Ethernet channel adapter parameters */
@@ -338,13 +338,13 @@ enum xsmp_xve_code {
 /** XSMP virtual Ethernet update bitmask */
 enum xsmp_xve_update {
 	/** Update MTU */
-	XSMP_XVE_UPDATE_MTU = ( 1 << 2 ),
+	XSMP_XVE_UPDATE_MTU = ( 1U << 2 ),
 	/** Update administrative state */
-	XSMP_XVE_UPDATE_STATE = ( 1 << 6 ),
+	XSMP_XVE_UPDATE_STATE = ( 1U << 6 ),
 	/** Update gateway to mark as down */
-	XSMP_XVE_UPDATE_GW_DOWN = ( 1 << 30 ),
+	XSMP_XVE_UPDATE_GW_DOWN = ( 1U << 30 ),
 	/** Update gateway information */
-	XSMP_XVE_UPDATE_GW_CHANGE = ( 1 << 31 ),
+	XSMP_XVE_UPDATE_GW_CHANGE = ( 1U << 31 ),
 };
 
 /** XSMP virtual Ethernet modes */