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efi_loader: printing UEFI revision in helloworld.efi

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We need to support multiple digits in the parts of the UEFI verision
number. E.g.

    EFI_SPECIFICATION_VERSION = (123 << 16) | 456

must be printed as

    123.45.6

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Heinrich Schuchardt 2022-09-01 22:23:47 +02:00
parent 67fe8cc001
commit a641e36fdb
1 changed files with 53 additions and 11 deletions
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64
lib/efi_loader/helloworld.c
View file

@ -29,24 +29,66 @@ static struct efi_system_table *systable;
static struct efi_boot_services *boottime; static struct efi_boot_services *boottime;
static struct efi_simple_text_output_protocol *con_out; static struct efi_simple_text_output_protocol *con_out;
/*
* Print an unsigned 32bit value as decimal number to an u16 string
*
* @value: value to be printed
* @buf: pointer to buffer address
* on return position of terminating zero word
*/
static void uint2dec(u32 value, u16 **buf)
{
u16 *pos = *buf;
int i;
u16 c;
u64 f;
/*
* Increment by .5 and multiply with
* (2 << 60) / 1,000,000,000 = 0x44B82FA0.9B5A52CC
* to move the first digit to bit 60-63.
*/
f = 0x225C17D0;
f += (0x9B5A52DULL * value) >> 28;
f += 0x44B82FA0ULL * value;
for (i = 0; i < 10; ++i) {
/* Write current digit */
c = f >> 60;
if (c || pos != *buf)
*pos++ = c + '0';
/* Eliminate current digit */
f &= 0xfffffffffffffff;
/* Get next digit */
f *= 0xaULL;
}
if (pos == *buf)
*pos++ = '0';
*pos = 0;
*buf = pos;
}
/** /**
* print_uefi_revision() - print UEFI revision number * print_uefi_revision() - print UEFI revision number
*/ */
static void print_uefi_revision(void) static void print_uefi_revision(void)
{ {
u16 rev[] = u"0.0.0"; u16 rev[13] = {0};
u16 *buf = rev;
u16 digit;
rev[0] = (systable->hdr.revision >> 16) + '0'; uint2dec(systable->hdr.revision >> 16, &buf);
rev[4] = systable->hdr.revision & 0xffff; *buf++ = '.';
for (; rev[4] >= 10;) { uint2dec(systable->hdr.revision & 0xffff, &buf);
rev[4] -= 10;
++rev[2]; /* Minor revision is only to be shown if non-zero */
digit = *--buf;
if (digit == '0') {
*buf = 0;
} else {
*buf++ = '.';
*buf = digit;
} }
/* Third digit is only to be shown if non-zero */
if (rev[4])
rev[4] += '0';
else
rev[3] = 0;
con_out->output_string(con_out, u"Running on UEFI "); con_out->output_string(con_out, u"Running on UEFI ");
con_out->output_string(con_out, rev); con_out->output_string(con_out, rev);