Add emulation for load/store register offset addressing mode (DDI 0487 C3.3.9). The offset register value is extended via UXTB/UXTH/UXTW/UXTX/SXTB/SXTH/SXTW/SXTX and optionally shifted by the element size.
Instruction coverage: - STR/LDR (GPR): register offset with extend, all sizes - STR/LDR (SIMD/FP): register offset with extend, 8-128 bit - PRFM register offset: NOP Signed-off-by: Lucas Amaral <[email protected]> --- target/arm/emulate/a64-ldst.decode | 29 ++++++++ target/arm/emulate/arm_emulate.c | 103 +++++++++++++++++++++++++++++ 2 files changed, 132 insertions(+) diff --git a/target/arm/emulate/a64-ldst.decode b/target/arm/emulate/a64-ldst.decode index c887dcba..af6babe1 100644 --- a/target/arm/emulate/a64-ldst.decode +++ b/target/arm/emulate/a64-ldst.decode @@ -10,6 +10,9 @@ # 'u' flag: 0 = 9-bit signed immediate (byte offset), 1 = 12-bit unsigned (needs << sz) &ldst_imm rt rn imm sz sign w p unpriv ext u +# Load/store register offset +&ldst rm rn rt sign ext sz opt s + ### Format templates # Load/store immediate (9-bit signed) @@ -21,6 +24,9 @@ # Load/store unsigned offset (12-bit, handler scales by << sz) @ldst_uimm .. ... . .. .. imm:12 rn:5 rt:5 &ldst_imm u=1 unpriv=0 p=0 w=0 +# Load/store register offset +@ldst .. ... . .. .. . rm:5 opt:3 s:1 .. rn:5 rt:5 &ldst + ### Load/store register — unscaled immediate (LDUR/STUR) # GPR @@ -122,6 +128,29 @@ STR_v_i 00 111 1 01 10 ............ ..... ..... @ldst_uimm sign= LDR_v_i sz:2 111 1 01 01 ............ ..... ..... @ldst_uimm sign=0 ext=0 LDR_v_i 00 111 1 01 11 ............ ..... ..... @ldst_uimm sign=0 ext=0 sz=4 +### Load/store register — register offset + +# GPR +STR sz:2 111 0 00 00 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=0 +LDR 00 111 0 00 01 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=1 sz=0 +LDR 01 111 0 00 01 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=1 sz=1 +LDR 10 111 0 00 01 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=1 sz=2 +LDR 11 111 0 00 01 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=0 sz=3 +LDR 00 111 0 00 10 1 ..... ... . 10 ..... ..... @ldst sign=1 ext=0 sz=0 +LDR 01 111 0 00 10 1 ..... ... . 10 ..... ..... @ldst sign=1 ext=0 sz=1 +LDR 10 111 0 00 10 1 ..... ... . 10 ..... ..... @ldst sign=1 ext=0 sz=2 +LDR 00 111 0 00 11 1 ..... ... . 10 ..... ..... @ldst sign=1 ext=1 sz=0 +LDR 01 111 0 00 11 1 ..... ... . 10 ..... ..... @ldst sign=1 ext=1 sz=1 + +# PRFM — register offset +NOP 11 111 0 00 10 1 ----- -1- - 10 ----- ----- + +# SIMD/FP +STR_v sz:2 111 1 00 00 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=0 +STR_v 00 111 1 00 10 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=0 sz=4 +LDR_v sz:2 111 1 00 01 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=0 +LDR_v 00 111 1 00 11 1 ..... ... . 10 ..... ..... @ldst sign=0 ext=0 sz=4 + ### System instructions — DC cache maintenance # SYS with CRn=C7 covers all data cache operations (DC CIVAC, CVAC, etc.). diff --git a/target/arm/emulate/arm_emulate.c b/target/arm/emulate/arm_emulate.c index 02fefc30..bf09e2a6 100644 --- a/target/arm/emulate/arm_emulate.c +++ b/target/arm/emulate/arm_emulate.c @@ -211,6 +211,109 @@ static bool trans_LDR_v_i(DisasContext *ctx, arg_ldst_imm *a) return true; } +/* Register offset extension (DDI 0487 C6.2.131) */ + +static uint64_t extend_reg(uint64_t val, int option, int shift) +{ + switch (option) { + case 0: /* UXTB */ + val = (uint8_t)val; + break; + case 1: /* UXTH */ + val = (uint16_t)val; + break; + case 2: /* UXTW */ + val = (uint32_t)val; + break; + case 3: /* UXTX / LSL */ + break; + case 4: /* SXTB */ + val = (int64_t)(int8_t)val; + break; + case 5: /* SXTH */ + val = (int64_t)(int16_t)val; + break; + case 6: /* SXTW */ + val = (int64_t)(int32_t)val; + break; + case 7: /* SXTX */ + break; + } + return val << shift; +} + +/* + * Load/store single -- register offset (GPR) + * STR / LDR (DDI 0487 C3.3.9) + */ + +static bool trans_STR(DisasContext *ctx, arg_ldst *a) +{ + int esize = (a->sz <= 3) ? (1 << a->sz) : 16; + int shift = a->s ? a->sz : 0; + uint64_t rm_val = gpr_read(ctx, a->rm); + uint64_t offset = extend_reg(rm_val, a->opt, shift); + uint64_t va = base_read(ctx, a->rn) + offset; + + uint64_t val = gpr_read(ctx, a->rt); + mem_write(ctx, va, &val, esize); + return true; +} + +static bool trans_LDR(DisasContext *ctx, arg_ldst *a) +{ + int esize = (a->sz <= 3) ? (1 << a->sz) : 16; + int shift = a->s ? a->sz : 0; + uint64_t rm_val = gpr_read(ctx, a->rm); + uint64_t offset = extend_reg(rm_val, a->opt, shift); + uint64_t va = base_read(ctx, a->rn) + offset; + uint64_t val = 0; + + if (mem_read(ctx, va, &val, esize) != 0) { + return true; + } + + val = load_extend(val, a->sz, a->sign, a->ext); + gpr_write(ctx, a->rt, val); + return true; +} + +/* + * Load/store single -- register offset (SIMD/FP) + * STR_v / LDR_v (DDI 0487 C3.3.10) + */ + +static bool trans_STR_v(DisasContext *ctx, arg_ldst *a) +{ + int esize = (a->sz <= 3) ? (1 << a->sz) : 16; + int shift = a->s ? a->sz : 0; + uint64_t rm_val = gpr_read(ctx, a->rm); + uint64_t offset = extend_reg(rm_val, a->opt, shift); + uint64_t va = base_read(ctx, a->rn) + offset; + uint8_t buf[16]; + + fpreg_read(ctx, a->rt, buf, esize); + mem_write(ctx, va, buf, esize); + return true; +} + +static bool trans_LDR_v(DisasContext *ctx, arg_ldst *a) +{ + int esize = (a->sz <= 3) ? (1 << a->sz) : 16; + int shift = a->s ? a->sz : 0; + uint64_t rm_val = gpr_read(ctx, a->rm); + uint64_t offset = extend_reg(rm_val, a->opt, shift); + uint64_t va = base_read(ctx, a->rn) + offset; + uint8_t buf[16]; + + if (mem_read(ctx, va, buf, esize) != 0) { + return true; + } + + fpreg_write(ctx, a->rt, buf, esize); + return true; +} + /* PRFM, DC cache maintenance -- treated as NOP */ static bool trans_NOP(DisasContext *ctx, arg_NOP *a) { -- 2.52.0
