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target/tricore: Fix tricore_tr_translate_insn

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we now fetch 2 bytes first, check whether we have a 32 bit insn, and only then
fetch another 2 bytes. We also make sure that a 16 bit insn that still fits
into the current page does not end up in the next page.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
This commit is contained in:
Bastian Koppelmann 2019-08-21 11:15:10 +02:00
parent 17ebc8c104
commit d4881da9b3
1 changed files with 34 additions and 13 deletions
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47
target/tricore/translate.c
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@ -8781,17 +8781,9 @@ static void decode_32Bit_opc(DisasContext *ctx)
}
}
static void decode_opc(DisasContext *ctx)
static bool tricore_insn_is_16bit(uint32_t insn)
{
/* 16-Bit Instruction */
if ((ctx->opcode & 0x1) == 0) {
ctx->pc_succ_insn = ctx->base.pc_next + 2;
decode_16Bit_opc(ctx);
/* 32-Bit Instruction */
} else {
ctx->pc_succ_insn = ctx->base.pc_next + 4;
decode_32Bit_opc(ctx);
}
return (insn & 0x1) == 0;
}
static void tricore_tr_init_disas_context(DisasContextBase *dcbase,
@ -8829,20 +8821,49 @@ static bool tricore_tr_breakpoint_check(DisasContextBase *dcbase, CPUState *cpu,
return true;
}
static bool insn_crosses_page(CPUTriCoreState *env, DisasContext *ctx)
{
/*
* Return true if the insn at ctx->base.pc_next might cross a page boundary.
* (False positives are OK, false negatives are not.)
* Our caller ensures we are only called if dc->base.pc_next is less than
* 4 bytes from the page boundary, so we cross the page if the first
* 16 bits indicate that this is a 32 bit insn.
*/
uint16_t insn = cpu_lduw_code(env, ctx->base.pc_next);
return !tricore_insn_is_16bit(insn);
}
static void tricore_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu)
{
DisasContext *ctx = container_of(dcbase, DisasContext, base);
CPUTriCoreState *env = cpu->env_ptr;
uint16_t insn_lo;
bool is_16bit;
ctx->opcode = cpu_ldl_code(env, ctx->base.pc_next);
decode_opc(ctx);
insn_lo = cpu_lduw_code(env, ctx->base.pc_next);
is_16bit = tricore_insn_is_16bit(insn_lo);
if (is_16bit) {
ctx->opcode = insn_lo;
ctx->pc_succ_insn = ctx->base.pc_next + 2;
decode_16Bit_opc(ctx);
} else {
uint32_t insn_hi = cpu_lduw_code(env, ctx->base.pc_next + 2);
ctx->opcode = insn_hi << 16 | insn_lo;
ctx->pc_succ_insn = ctx->base.pc_next + 4;
decode_32Bit_opc(ctx);
}
ctx->base.pc_next = ctx->pc_succ_insn;
if (ctx->base.is_jmp == DISAS_NEXT) {
target_ulong page_start;
page_start = ctx->base.pc_first & TARGET_PAGE_MASK;
if (ctx->base.pc_next - page_start >= TARGET_PAGE_SIZE) {
if (ctx->base.pc_next - page_start >= TARGET_PAGE_SIZE
|| (ctx->base.pc_next - page_start >= TARGET_PAGE_SIZE - 3
&& insn_crosses_page(env, ctx))) {
ctx->base.is_jmp = DISAS_TOO_MANY;
}
}