Hello, is it really a bug?

----
Bruno Prado


On Fri, Oct 2, 2020 at 8:09 AM Bruno Prado <bruno@dcomp.ufs.br> wrote:

> I am including some syscall functions:
>
> int _fstat(int file, struct stat* st) {
>        register int value asm("r0");
>        uint32_t p[] = { file };
>        R0(0x0C);
>        R1(p);
>        BKPT();
>        return value;
> }
>
> int _read(int file, char* ptr, int len) {
>        register int value asm("r0");
>        uint32_t p[] = { file, (uint32_t)(ptr), len };
>        R0(0x06);
>        R1(p);
>        BKPT();
>        return value;
> }
>
> int _write(int file, char* ptr, int len) {
>        register int value asm("r0");
>        uint32_t p[] = { file, (uint32_t)(ptr), len };
>        R0(0x05);
>        R1(p);
>        BKPT();
>        return value;
> }
>
> Also the interruption output from execution:
>
> $ qemu-system-arm -M netduino2 -nographic -semihosting -kernel vp2.bin -d
> int
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x1
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x1
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x1
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x1
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0xc
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x5
> What is your name?
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x5
> Reading from file...
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0xc
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x6
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0xc
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x6
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x5
> My name is Turing
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x5
> I am alive!!!
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0xa
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0xa
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x2
> Taking exception 16 [Semihosting call]
> ...handling as semihosting call 0x20
>
> Could you please provide any working example using ARM semihosting on
> stdin?
>
> Thanks,
> ----
> Bruno Prado
>
>
> On Fri, Oct 2, 2020 at 7:25 AM Peter Maydell <peter.maydell@linaro.org>
> wrote:
>
>> On Thu, 1 Oct 2020 at 22:21, Bruno Prado <bruno@dcomp.ufs.br> wrote:
>> > Thanks for the reply... I am attaching some code and output:
>> >
>> > #include <stdio.h>
>> > int main() {
>> >        char name[50] = "Nobody";
>> >        FILE* file = fopen("name", "r");
>> >        printf("What is your name?\n");
>> >        fprintf(stdout, "Reading from file...\n");
>> >        fscanf(file, "%s", name);
>> >        fscanf(stdin, "%s", name);
>> >        printf("My name is %s\n", name);
>> >        fprintf(stderr, "I am alive!!!\n");
>> >        fclose(file);
>> >        return 0;
>> > }
>>
>> This is not making direct semihosting calls. The behaviour
>> of these function calls will depend on whatever the C
>> standard library implementation you're linking with is doing.
>>
>> You're not checking for errors from any of your function
>> calls, incidentally.
>>
>> thanks
>> -- PMM
>>
>