From 0f11f25a001f6adca18689192182d415ff3dbb7c Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Thu, 6 Jan 2011 22:43:13 +0100 Subject: tcg/arm: improve constant loading Improve constant loading in two ways: - On all ARM versions, it's possible to load 0xffffff00 = -0x100 using the mvn rd, #0. Fix the conditions. - On <= ARMv6 versions, where movw and movt are not available, load the constants using mov and orr with rotations depending on the constant to load. This is very useful for example to load constants where the low byte is 0. This reduce the generated code size by about 7%. Also fix the coding style at the same time. Cc: Andrzej Zaborowski Signed-off-by: Aurelien Jarno --- tcg/arm/tcg-target.c | 39 +++++++++++++++++++++------------------ 1 file changed, 21 insertions(+), 18 deletions(-) diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c index 08c44c112..1eb5605f8 100644 --- a/tcg/arm/tcg-target.c +++ b/tcg/arm/tcg-target.c @@ -406,35 +406,38 @@ static inline void tcg_out_dat_imm(TCGContext *s, } static inline void tcg_out_movi32(TCGContext *s, - int cond, int rd, int32_t arg) + int cond, int rd, uint32_t arg) { /* TODO: This is very suboptimal, we can easily have a constant * pool somewhere after all the instructions. */ - - if (arg < 0 && arg > -0x100) - return tcg_out_dat_imm(s, cond, ARITH_MVN, rd, 0, (~arg) & 0xff); - - if (use_armv7_instructions) { + if ((int)arg < 0 && (int)arg >= -0x100) { + tcg_out_dat_imm(s, cond, ARITH_MVN, rd, 0, (~arg) & 0xff); + } else if (use_armv7_instructions) { /* use movw/movt */ /* movw */ tcg_out32(s, (cond << 28) | 0x03000000 | (rd << 12) | ((arg << 4) & 0x000f0000) | (arg & 0xfff)); - if (arg & 0xffff0000) + if (arg & 0xffff0000) { /* movt */ tcg_out32(s, (cond << 28) | 0x03400000 | (rd << 12) | ((arg >> 12) & 0x000f0000) | ((arg >> 16) & 0xfff)); - } else { - tcg_out_dat_imm(s, cond, ARITH_MOV, rd, 0, arg & 0xff); - if (arg & 0x0000ff00) - tcg_out_dat_imm(s, cond, ARITH_ORR, rd, rd, - ((arg >> 8) & 0xff) | 0xc00); - if (arg & 0x00ff0000) - tcg_out_dat_imm(s, cond, ARITH_ORR, rd, rd, - ((arg >> 16) & 0xff) | 0x800); - if (arg & 0xff000000) - tcg_out_dat_imm(s, cond, ARITH_ORR, rd, rd, - ((arg >> 24) & 0xff) | 0x400); } + } else { + int opc = ARITH_MOV; + int rn = 0; + + do { + int i, rot; + + i = ctz32(arg) & ~1; + rot = ((32 - i) << 7) & 0xf00; + tcg_out_dat_imm(s, cond, opc, rd, rn, ((arg >> i) & 0xff) | rot); + arg &= ~(0xff << i); + + opc = ARITH_ORR; + rn = rd; + } while (arg); + } } static inline void tcg_out_mul32(TCGContext *s, -- cgit v1.2.3