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authorPeter Maydell <peter.maydell@linaro.org>2011-02-03 19:43:25 +0000
committerAurelien Jarno <aurelien@aurel32.net>2011-02-04 21:30:15 +0100
commita2fdc8907bee6eb572fea992be7126e1b616d5bf (patch)
tree4c1c427c99b2161bb55869c3c165ceb84009cffc /target-arm
parent3d185e5dd4967b7d03772d806ee566ed09d67485 (diff)
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target-arm: Fix decoding of Thumb preload and hint space
Refine the decoding of the Thumb preload and hint space, so we UNDEF on the patterns that are supposed to UNDEF rather than NOP. We also move the tests for this space earlier, so we don't emit harmless but unnecessary address generation code for preload hints (which by their nature are likely to be in hot code paths). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Diffstat (limited to 'target-arm')
-rw-r--r--target-arm/translate.c70
1 files changed, 48 insertions, 22 deletions
diff --git a/target-arm/translate.c b/target-arm/translate.c
index a8f1ffe..e4649e6 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -8306,6 +8306,42 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1)
goto illegal_op;
break;
}
+ op = ((insn >> 21) & 3) | ((insn >> 22) & 4);
+ if (rs == 15) {
+ if (!(insn & (1 << 20))) {
+ goto illegal_op;
+ }
+ if (op != 2) {
+ /* Byte or halfword load space with dest == r15 : memory hints.
+ * Catch them early so we don't emit pointless addressing code.
+ * This space is a mix of:
+ * PLD/PLDW/PLI, which we implement as NOPs (note that unlike
+ * the ARM encodings, PLDW space doesn't UNDEF for non-v7MP
+ * cores)
+ * unallocated hints, which must be treated as NOPs
+ * UNPREDICTABLE space, which we NOP or UNDEF depending on
+ * which is easiest for the decoding logic
+ * Some space which must UNDEF
+ */
+ int op1 = (insn >> 23) & 3;
+ int op2 = (insn >> 6) & 0x3f;
+ if (op & 2) {
+ goto illegal_op;
+ }
+ if (rn == 15) {
+ /* UNPREDICTABLE or unallocated hint */
+ return 0;
+ }
+ if (op1 & 1) {
+ return 0; /* PLD* or unallocated hint */
+ }
+ if ((op2 == 0) || ((op2 & 0x3c) == 0x30)) {
+ return 0; /* PLD* or unallocated hint */
+ }
+ /* UNDEF space, or an UNPREDICTABLE */
+ return 1;
+ }
+ }
user = IS_USER(s);
if (rn == 15) {
addr = new_tmp();
@@ -8324,9 +8360,8 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1)
imm = insn & 0xfff;
tcg_gen_addi_i32(addr, addr, imm);
} else {
- op = (insn >> 8) & 7;
imm = insn & 0xff;
- switch (op) {
+ switch ((insn >> 8) & 7) {
case 0: case 8: /* Shifted Register. */
shift = (insn >> 4) & 0xf;
if (shift > 3)
@@ -8363,32 +8398,23 @@ static int disas_thumb2_insn(CPUState *env, DisasContext *s, uint16_t insn_hw1)
}
}
}
- op = ((insn >> 21) & 3) | ((insn >> 22) & 4);
if (insn & (1 << 20)) {
/* Load. */
- if (rs == 15 && op != 2) {
- if (op & 2)
- goto illegal_op;
- /* Memory hint. Implemented as NOP. */
+ switch (op) {
+ case 0: tmp = gen_ld8u(addr, user); break;
+ case 4: tmp = gen_ld8s(addr, user); break;
+ case 1: tmp = gen_ld16u(addr, user); break;
+ case 5: tmp = gen_ld16s(addr, user); break;
+ case 2: tmp = gen_ld32(addr, user); break;
+ default: goto illegal_op;
+ }
+ if (rs == 15) {
+ gen_bx(s, tmp);
} else {
- switch (op) {
- case 0: tmp = gen_ld8u(addr, user); break;
- case 4: tmp = gen_ld8s(addr, user); break;
- case 1: tmp = gen_ld16u(addr, user); break;
- case 5: tmp = gen_ld16s(addr, user); break;
- case 2: tmp = gen_ld32(addr, user); break;
- default: goto illegal_op;
- }
- if (rs == 15) {
- gen_bx(s, tmp);
- } else {
- store_reg(s, rs, tmp);
- }
+ store_reg(s, rs, tmp);
}
} else {
/* Store. */
- if (rs == 15)
- goto illegal_op;
tmp = load_reg(s, rs);
switch (op) {
case 0: gen_st8(tmp, addr, user); break;