Incorrect usage of 'Val instead of 'Enum_Val

[liampwll]

The below line will raise a Constraint_Error if Range_Check is enabled as the enumeration is not continuous, using 'Enum_Val instead would fix this. This error could exist in the other uses of 'Val which I have not checked and it could have potentially worse consequences than this one which will likely be harmless when Range_Check is disabled.

Ada_Drivers_Library/arch/ARM/STM32/drivers/stm32-adc.adb

Line 410 in b651d01

if Multi_ADC_Mode_Selections'Val (C_ADC_Periph.CCR.MULT) = Independent

[pat-rogers]

On 13-Jun-24 2:24 AM, Liam Powell wrote: Here is another case of the same error, this one can return an incorrect value: https://github.com/AdaCore/Ada_Drivers_Library/blob/b651d01dcfd7e27836f938c1d494e1ed3212ed43/arch/ARM/STM32/drivers/stm32-gpio.adb#L439 <https://github.com/AdaCore/Ada_Drivers_Library/blob/b651d01dcfd7e27836f938c1d494e1ed3212ed43/arch/ARM/STM32/drivers/stm32-gpio.adb#L439>

Thank you for opening this issue. I have not yet looked at the first example, but I believe that the code in this second example case is correct. Specifically, in the following: return EXTI.External_Line_Number'Val (GPIO_Pin'Pos (This.Pin)); is correct because: * type External_Line_Number does not have a representation clause, therefore the representation values are zero-based (ie, 0 through 22), and * the result of 'Pos is always zero-based, so GPIO_Pin'Pos returns 0 .. 15, and * 0 .. 15 are valid representations for External_Line_Number values when converted via 'Val, and * those numeric values result in the External_Line_Number values that match the corresponding GPIO pins. Let me know if you disagree. It is always possible that I have missed something. In any case I will also look at the first example in the issue. Thanks again, Pat Rogers

[liampwll]

I have since removed that one but GitHub obviously can not update the email, it was only problematic in a fork rather than this repo. The first one is still an issue with Range_Check.

…

On Tue, Aug 13, 2024 at 2:22 AM Pat Rogers ***@***.***> wrote: On 13-Jun-24 2:24 AM, Liam Powell wrote: > Here is another case of the same error, this one can return an incorrect > value: > > https://github.com/AdaCore/Ada_Drivers_Library/blob/b651d01dcfd7e27836f938c1d494e1ed3212ed43/arch/ARM/STM32/drivers/stm32-gpio.adb#L439 < https://github.com/AdaCore/Ada_Drivers_Library/blob/b651d01dcfd7e27836f938c1d494e1ed3212ed43/arch/ARM/STM32/drivers/stm32-gpio.adb#L439 > Thank you for opening this issue. I have not yet looked at the first example, but I believe that the code in this second example case is correct. Specifically, in the following: return EXTI.External_Line_Number'Val (GPIO_Pin'Pos (This.Pin)); is correct because: * type External_Line_Number does not have a representation clause, therefore the representation values are zero-based (ie, 0 through 22), and * the result of 'Pos is always zero-based, so GPIO_Pin'Pos returns 0 .. 15, and * 0 .. 15 are valid representations for External_Line_Number values when converted via 'Val, and * those numeric values result in the External_Line_Number values that match the corresponding GPIO pins. Let me know if you disagree. It is always possible that I have missed something. In any case I will also look at the first example in the issue. Thanks again, Pat Rogers — Reply to this email directly, view it on GitHub <#431 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AANZQULYDJACYHH243DTMXDZRD4NJAVCNFSM6AAAAABJHYTHKOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDEOBUGY2DONRWGM> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[pat-rogers]

On 12-Aug-24 1:25 PM, Liam Powell wrote: I have since removed that one but GitHub obviously can not update the email, it was only problematic in a fork rather than this repo. The first one is still an issue with Range_Check.

OK, I'll take a look. Pat

[pat-rogers]

On 13-Jun-24 2:14 AM, Liam Powell wrote: The below line will raise a Constraint_Error if Range_Check is enabled as the enumeration is not continuous, using 'Enum_Val instead would fix this. This error could exist in the thousands of other uses of 'Val which I have not checked and it could have potentially worse consequences than this one which will likely be harmless when Range_Check is disabled. https://github.com/AdaCore/Ada_Drivers_Library/blob/b651d01dcfd7e27836f938c1d494e1ed3212ed43/arch/ARM/STM32/drivers/stm32-adc.adb#L410 <https://github.com/AdaCore/Ada_Drivers_Library/blob/b651d01dcfd7e27836f938c1d494e1ed3212ed43/arch/ARM/STM32/drivers/stm32-adc.adb#L410>

I agree that using 'Val in this line is incorrect.