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[POWERPC] Emulate isel (Integer Select) instruction

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isel (Integer Select) is a new user space instruction in the
PowerISA 2.04 spec.  Not all processors implement it so lets emulate
to ensure code built with isel will run everywhere.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Kumar Gala 2007-11-19 21:35:29 -06:00
parent fd351b8920
commit c1469f13de
1 changed files with 25 additions and 0 deletions

25
arch/powerpc/kernel/traps.c
View file

@ -622,6 +622,9 @@ static void parse_fpe(struct pt_regs *regs)
#define INST_POPCNTB 0x7c0000f4
#define INST_POPCNTB_MASK 0xfc0007fe
#define INST_ISEL 0x7c00001e
#define INST_ISEL_MASK 0xfc00003e
static int emulate_string_inst(struct pt_regs *regs, u32 instword)
{
u8 rT = (instword >> 21) & 0x1f;
@ -707,6 +710,23 @@ static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword)
return 0;
}
static int emulate_isel(struct pt_regs *regs, u32 instword)
{
u8 rT = (instword >> 21) & 0x1f;
u8 rA = (instword >> 16) & 0x1f;
u8 rB = (instword >> 11) & 0x1f;
u8 BC = (instword >> 6) & 0x1f;
u8 bit;
unsigned long tmp;
tmp = (rA == 0) ? 0 : regs->gpr[rA];
bit = (regs->ccr >> (31 - BC)) & 0x1;
regs->gpr[rT] = bit ? tmp : regs->gpr[rB];
return 0;
}
static int emulate_instruction(struct pt_regs *regs)
{
u32 instword;
@ -749,6 +769,11 @@ static int emulate_instruction(struct pt_regs *regs)
return emulate_popcntb_inst(regs, instword);
}
/* Emulate isel (Integer Select) instruction */
if ((instword & INST_ISEL_MASK) == INST_ISEL) {
return emulate_isel(regs, instword);
}
return -EINVAL;
}