arm64: introduce mov_q macro to move a constant into a 64-bit register

Implement a macro mov_q that can be used to move an immediate constant
into a 64-bit register, using between 2 and 4 movz/movk instructions
(depending on the operand)

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 972fb55..f9b6f7a 100644 (file)
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -221,4 +221,24 @@ lr .req    x30             // link register
        .long   \sym\()_hi32
        .endm
 
+       /*
+        * mov_q - move an immediate constant into a 64-bit register using
+        *         between 2 and 4 movz/movk instructions (depending on the
+        *         magnitude and sign of the operand)
+        */
+       .macro  mov_q, reg, val
+       .if (((\val) >> 31) == 0 || ((\val) >> 31) == 0x1ffffffff)
+       movz    \reg, :abs_g1_s:\val
+       .else
+       .if (((\val) >> 47) == 0 || ((\val) >> 47) == 0x1ffff)
+       movz    \reg, :abs_g2_s:\val
+       .else
+       movz    \reg, :abs_g3:\val
+       movk    \reg, :abs_g2_nc:\val
+       .endif
+       movk    \reg, :abs_g1_nc:\val
+       .endif
+       movk    \reg, :abs_g0_nc:\val
+       .endm
+
 #endif /* __ASM_ASSEMBLER_H */