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[ARM32] do not clear CPSR.E when updating flags #2158

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[ARM32] do not clear CPSR.E when updating flags #2158

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585a8b2
[ARM32] do not change CPSR.E when updating flags
kittennbfive Apr 12, 2025
6549abc
add unit test
kittennbfive Apr 12, 2025
d8faa33
fix formatting...
kittennbfive Apr 12, 2025
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2 changes: 1 addition & 1 deletion qemu/target/arm/internals.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1125,7 +1125,7 @@ static inline uint32_t aarch32_cpsr_valid_mask(uint64_t features,
valid |= CPSR_Q; /* V5TE in reality*/
}
if ((features >> ARM_FEATURE_V6) & 1) {
valid |= CPSR_E | CPSR_GE;
valid |= CPSR_GE;
}
if ((features >> ARM_FEATURE_THUMB2) & 1) {
valid |= CPSR_IT;
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32 changes: 32 additions & 0 deletions tests/unit/test_arm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -956,6 +956,37 @@ static void test_arm_cp15_c1_c0_2(void)
OK(uc_close(uc));
}

static void test_arm_be_flags(void)
{
uc_engine *uc;
/*
subs pc, lr, #4 //<------ mind the 's' == update flags
nop
nop
nop
*/
const uint8_t code[] = { 0xe2, 0x5e, 0xf0, 0x04, 0xe3, 0x20, 0xf0, 0x00, 0xe3, 0x20, 0xf0, 0x00, 0x20, 0xf0, 0x00 };
uint32_t reg;

// Initialize emulator in ARM BE mode
OK(uc_open(UC_ARCH_ARM, UC_MODE_ARM|UC_MODE_BIG_ENDIAN, &uc));
OK(uc_mem_map(uc, code_start, 4096, UC_PROT_ALL));
OK(uc_mem_write(uc, code_start, code, sizeof(code)));

// Set LR
reg = code_start + 0x0c;
OK(uc_reg_write(uc, UC_ARM_REG_LR, &reg));

// Run
OK(uc_emu_start(uc, code_start, code_start + sizeof(code), 0, 3));

// Check CPSR.E, should be set
OK(uc_reg_read(uc, UC_ARM_REG_CPSR, &reg));
TEST_CHECK((!!(reg&(1<<9)))==1);

OK(uc_close(uc));
}

TEST_LIST = {{"test_arm_nop", test_arm_nop},
{"test_arm_thumb_sub", test_arm_thumb_sub},
{"test_armeb_sub", test_armeb_sub},
Expand Down Expand Up @@ -985,4 +1016,5 @@ TEST_LIST = {{"test_arm_nop", test_arm_nop},
{"test_arm_tcg_opcode_cmp", test_arm_tcg_opcode_cmp},
{"test_arm_thumb_tcg_opcode_cmn", test_arm_thumb_tcg_opcode_cmn},
{"test_arm_cp15_c1_c0_2", test_arm_cp15_c1_c0_2},
{"test_arm_be_flags", test_arm_be_flags},
{NULL, NULL}};
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