For m68k CPUs that do not support unaligned accesses, any such access should
cause the CPU to raise an Address Error exception.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
target/m68k/cpu.c | 1 +
target/m68k/cpu.h | 4 ++++
target/m68k/op_helper.c | 11 +++++++++++
3 files changed, 16 insertions(+)
diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
index efd6bbded8..25e95f9f68 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -538,6 +538,7 @@ static const TCGCPUOps m68k_tcg_ops = {
.cpu_exec_interrupt = m68k_cpu_exec_interrupt,
.do_interrupt = m68k_cpu_do_interrupt,
.do_transaction_failed = m68k_cpu_transaction_failed,
+ .do_unaligned_access = m68k_cpu_do_unaligned_access,
#endif /* !CONFIG_USER_ONLY */
};
diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
index b5bbeedb7a..d4c9531b1c 100644
--- a/target/m68k/cpu.h
+++ b/target/m68k/cpu.h
@@ -590,6 +590,10 @@ void m68k_cpu_transaction_failed(CPUState *cs, hwaddr physaddr, vaddr addr,
unsigned size, MMUAccessType access_type,
int mmu_idx, MemTxAttrs attrs,
MemTxResult response, uintptr_t retaddr);
+G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
+ MMUAccessType access_type,
+ int mmu_idx,
+ uintptr_t retaddr);
#endif
#include "exec/cpu-all.h"
diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c
index 15bad5dd46..417b691d8d 100644
--- a/target/m68k/op_helper.c
+++ b/target/m68k/op_helper.c
@@ -558,6 +558,17 @@ raise_exception_format2(CPUM68KState *env, int tt, int ilen, uintptr_t raddr)
cpu_loop_exit(cs);
}
+#if !defined(CONFIG_USER_ONLY)
+G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
+ MMUAccessType access_type,
+ int mmu_idx, uintptr_t retaddr)
+{
+ CPUM68KState *env = cpu_env(cs);
+
+ raise_exception(env, EXCP_ADDRESS);
+}
+#endif
+
void HELPER(divuw)(CPUM68KState *env, int destr, uint32_t den, int ilen)
{
uint32_t num = env->dregs[destr];
--
2.39.2On 6/23/24 04:57, Mark Cave-Ayland wrote:
> +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> + MMUAccessType access_type,
> + int mmu_idx, uintptr_t retaddr)
> +{
> + CPUM68KState *env = cpu_env(cs);
> +
> + raise_exception(env, EXCP_ADDRESS);
> +}
Surely the address gets stored in the exception frame somewhere?
r~
On 23/06/2024 20:47, Richard Henderson wrote:
> On 6/23/24 04:57, Mark Cave-Ayland wrote:
>> +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
>> + MMUAccessType access_type,
>> + int mmu_idx, uintptr_t retaddr)
>> +{
>> + CPUM68KState *env = cpu_env(cs);
>> +
>> + raise_exception(env, EXCP_ADDRESS);
>> +}
>
> Surely the address gets stored in the exception frame somewhere?
>
> r~
Well. There is already some logic there for EXCP_ADDRESS in m68k_interrupt_all() so I
thought this would just work as-is, but upon closer reading of older CPU datasheets
it appears there are at least 2 different stack frame formats for CPUs before the 68040.
It looks like I'll have to do a bit more research before posting a v2.
ATB,
Mark.
On Sun, 23 Jun 2024, Mark Cave-Ayland wrote:
> For m68k CPUs that do not support unaligned accesses, any such access should
> cause the CPU to raise an Address Error exception.
>
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
> target/m68k/cpu.c | 1 +
> target/m68k/cpu.h | 4 ++++
> target/m68k/op_helper.c | 11 +++++++++++
> 3 files changed, 16 insertions(+)
>
> diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
> index efd6bbded8..25e95f9f68 100644
> --- a/target/m68k/cpu.c
> +++ b/target/m68k/cpu.c
> @@ -538,6 +538,7 @@ static const TCGCPUOps m68k_tcg_ops = {
> .cpu_exec_interrupt = m68k_cpu_exec_interrupt,
> .do_interrupt = m68k_cpu_do_interrupt,
> .do_transaction_failed = m68k_cpu_transaction_failed,
> + .do_unaligned_access = m68k_cpu_do_unaligned_access,
> #endif /* !CONFIG_USER_ONLY */
Why is it sysemu only? Shouldn't user mode cpu only emulation do the same?
I also don't get how this is restricted to pre 68020 CPUs or account for
differences between data and inst fetch on 20+ but I may be missing
somerhing as I don't know this code or 68k behaviour well. So this is just
a question, I'm not saying it's wrong but I don't understand why it's
right.
Regards,
BALATON Zoltan
> };
>
> diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
> index b5bbeedb7a..d4c9531b1c 100644
> --- a/target/m68k/cpu.h
> +++ b/target/m68k/cpu.h
> @@ -590,6 +590,10 @@ void m68k_cpu_transaction_failed(CPUState *cs, hwaddr physaddr, vaddr addr,
> unsigned size, MMUAccessType access_type,
> int mmu_idx, MemTxAttrs attrs,
> MemTxResult response, uintptr_t retaddr);
> +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> + MMUAccessType access_type,
> + int mmu_idx,
> + uintptr_t retaddr);
> #endif
>
> #include "exec/cpu-all.h"
> diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c
> index 15bad5dd46..417b691d8d 100644
> --- a/target/m68k/op_helper.c
> +++ b/target/m68k/op_helper.c
> @@ -558,6 +558,17 @@ raise_exception_format2(CPUM68KState *env, int tt, int ilen, uintptr_t raddr)
> cpu_loop_exit(cs);
> }
>
> +#if !defined(CONFIG_USER_ONLY)
> +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
> + MMUAccessType access_type,
> + int mmu_idx, uintptr_t retaddr)
> +{
> + CPUM68KState *env = cpu_env(cs);
> +
> + raise_exception(env, EXCP_ADDRESS);
> +}
> +#endif
> +
> void HELPER(divuw)(CPUM68KState *env, int destr, uint32_t den, int ilen)
> {
> uint32_t num = env->dregs[destr];
>
On 23/06/2024 16:11, BALATON Zoltan wrote:
> On Sun, 23 Jun 2024, Mark Cave-Ayland wrote:
>> For m68k CPUs that do not support unaligned accesses, any such access should
>> cause the CPU to raise an Address Error exception.
>>
>> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>> ---
>> target/m68k/cpu.c | 1 +
>> target/m68k/cpu.h | 4 ++++
>> target/m68k/op_helper.c | 11 +++++++++++
>> 3 files changed, 16 insertions(+)
>>
>> diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
>> index efd6bbded8..25e95f9f68 100644
>> --- a/target/m68k/cpu.c
>> +++ b/target/m68k/cpu.c
>> @@ -538,6 +538,7 @@ static const TCGCPUOps m68k_tcg_ops = {
>> .cpu_exec_interrupt = m68k_cpu_exec_interrupt,
>> .do_interrupt = m68k_cpu_do_interrupt,
>> .do_transaction_failed = m68k_cpu_transaction_failed,
>> + .do_unaligned_access = m68k_cpu_do_unaligned_access,
>> #endif /* !CONFIG_USER_ONLY */
>
> Why is it sysemu only? Shouldn't user mode cpu only emulation do the same? I also
> don't get how this is restricted to pre 68020 CPUs or account for differences between
> data and inst fetch on 20+ but I may be missing somerhing as I don't know this code
> or 68k behaviour well. So this is just a question, I'm not saying it's wrong but I
> don't understand why it's right.
I'm not exactly sure, but I'm guessing that this is handled by the host user code
since all CPUs that implement do_unaligned_access do so in a block contained within
#ifndef CONFIG_USER_ONLY ... #endif.
ATB,
Mark.
© 2016 - 2026 Red Hat, Inc.