Fix always-true comparison warning in pio_insn (#2608)

earlephilhower · web-flow · commit ad2f4143ebec · 2025-09-10T10:18:22.000-05:00
The sideset_bit_count in pio_encode_sideset_opt is unsigned, so any comparison "sideset_bit_count >= 0" will always be true. GCC with pedantic warnings will complain when this happens. Remove the unneeded >=0 portion of the parameter validity check. Fixes #2607
diff --git a/src/rp2_common/hardware_pio/include/hardware/pio_instructions.h b/src/rp2_common/hardware_pio/include/hardware/pio_instructions.h
@@ -148,7 +148,7 @@ static inline uint pio_encode_sideset(uint sideset_bit_count, uint value) {
  * \return the side set bits to be ORed with an instruction encoding
  */
 static inline uint pio_encode_sideset_opt(uint sideset_bit_count, uint value) {
-    valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count >= 0 && sideset_bit_count <= 4);
+    valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count <= 4);
     valid_params_if(PIO_INSTRUCTIONS, value <= ((1u << sideset_bit_count) - 1));
     return 0x1000u | value << (12u - sideset_bit_count);
 }

Original file line number	Diff line number	Diff line change
`@@ -148,7 +148,7 @@ static inline uint pio_encode_sideset(uint sideset_bit_count, uint value) {`
`148`	`148`	`* \return the side set bits to be ORed with an instruction encoding`
`149`	`149`	`*/`
`150`	`150`	`static inline uint pio_encode_sideset_opt(uint sideset_bit_count, uint value) {`
`151`		`- valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count >= 0 && sideset_bit_count <= 4);`
	`151`	`+ valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count <= 4);`
`152`	`152`	`valid_params_if(PIO_INSTRUCTIONS, value <= ((1u << sideset_bit_count) - 1));`
`153`	`153`	`return 0x1000u \| value << (12u - sideset_bit_count);`
`154`	`154`	`}`