[PATCH v39 08/22] target/avr: Add instruction translation - Bit and Bit-test Instructions

[Michael Rolnik]

This includes:
    - LSR, ROR
    - ASR
    - SWAP
    - SBI, CBI
    - BST, BLD
    - BSET, BCLR

Signed-off-by: Michael Rolnik <address@hidden>
---
 target/avr/translate.c | 235 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 235 insertions(+)

diff --git a/target/avr/translate.c b/target/avr/translate.c
index 950504f7d0..e303a1f4cc 100644
--- a/target/avr/translate.c
+++ b/target/avr/translate.c
@@ -2371,3 +2371,238 @@ static bool trans_LAT(DisasContext *ctx, arg_LAT *a)
 
     return true;
 }
+
+/*
+ * Bit and Bit-test Instructions
+ */
+static void gen_rshift_ZNVSf(TCGv R)
+{
+    tcg_gen_setcondi_tl(TCG_COND_EQ, cpu_Zf, R, 0); /* Zf = R == 0 */
+    tcg_gen_shri_tl(cpu_Nf, R, 7); /* Nf = R(7) */
+    tcg_gen_xor_tl(cpu_Vf, cpu_Nf, cpu_Cf);
+    tcg_gen_xor_tl(cpu_Sf, cpu_Nf, cpu_Vf); /* Sf = Nf ^ Vf */
+}
+
+/*
+ *  Shifts all bits in Rd one place to the right. Bit 7 is cleared. Bit 0 is
+ *  loaded into the C Flag of the SREG. This operation effectively divides an
+ *  unsigned value by two. The C Flag can be used to round the result.
+ */
+static bool trans_LSR(DisasContext *ctx, arg_LSR *a)
+{
+    TCGv Rd = cpu_r[a->rd];
+
+    tcg_gen_andi_tl(cpu_Cf, Rd, 1);
+    tcg_gen_shri_tl(Rd, Rd, 1);
+    tcg_gen_setcondi_tl(TCG_COND_EQ, cpu_Zf, Rd, 0); /* Zf = Rd == 0 */
+    tcg_gen_movi_tl(cpu_Nf, 0);
+    tcg_gen_mov_tl(cpu_Vf, cpu_Cf);
+    tcg_gen_mov_tl(cpu_Sf, cpu_Vf);
+
+    return true;
+}
+
+/*
+ *  Shifts all bits in Rd one place to the right. The C Flag is shifted into
+ *  bit 7 of Rd. Bit 0 is shifted into the C Flag.  This operation, combined
+ *  with ASR, effectively divides multi-byte signed values by two. Combined 
with
+ *  LSR it effectively divides multi-byte unsigned values by two. The Carry 
Flag
+ *  can be used to round the result.
+ */
+static bool trans_ROR(DisasContext *ctx, arg_ROR *a)
+{
+    TCGv Rd = cpu_r[a->rd];
+    TCGv t0 = tcg_temp_new_i32();
+
+    tcg_gen_shli_tl(t0, cpu_Cf, 7);
+    tcg_gen_andi_tl(cpu_Cf, Rd, 1);
+    tcg_gen_shri_tl(Rd, Rd, 1);
+    tcg_gen_or_tl(Rd, Rd, t0);
+    gen_rshift_ZNVSf(Rd);
+
+    tcg_temp_free_i32(t0);
+
+    return true;
+}
+
+/*
+ *  Shifts all bits in Rd one place to the right. Bit 7 is held constant. Bit 0
+ *  is loaded into the C Flag of the SREG. This operation effectively divides a
+ *  signed value by two without changing its sign. The Carry Flag can be used 
to
+ *  round the result.
+ */
+static bool trans_ASR(DisasContext *ctx, arg_ASR *a)
+{
+    TCGv Rd = cpu_r[a->rd];
+    TCGv t0 = tcg_temp_new_i32();
+
+    tcg_gen_andi_tl(cpu_Cf, Rd, 1); /* Cf = Rd(0) */
+    tcg_gen_andi_tl(t0, Rd, 0x80); /* Rd = (Rd & 0x80) | (Rd >> 1) */
+    tcg_gen_shri_tl(Rd, Rd, 1);
+    tcg_gen_or_tl(Rd, Rd, t0);
+
+    gen_rshift_ZNVSf(Rd);
+
+    tcg_temp_free_i32(t0);
+
+    return true;
+}
+
+/*
+ *  Swaps high and low nibbles in a register.
+ */
+static bool trans_SWAP(DisasContext *ctx, arg_SWAP *a)
+{
+    TCGv Rd = cpu_r[a->rd];
+    TCGv t0 = tcg_temp_new_i32();
+    TCGv t1 = tcg_temp_new_i32();
+
+    tcg_gen_andi_tl(t0, Rd, 0x0f);
+    tcg_gen_shli_tl(t0, t0, 4);
+    tcg_gen_andi_tl(t1, Rd, 0xf0);
+    tcg_gen_shri_tl(t1, t1, 4);
+    tcg_gen_or_tl(Rd, t0, t1);
+
+    tcg_temp_free_i32(t1);
+    tcg_temp_free_i32(t0);
+
+    return true;
+}
+
+/*
+ *  Sets a specified bit in an I/O Register. This instruction operates on
+ *  the lower 32 I/O Registers -- addresses 0-31.
+ */
+static bool trans_SBI(DisasContext *ctx, arg_SBI *a)
+{
+    TCGv data = tcg_temp_new_i32();
+    TCGv port = tcg_const_i32(a->reg);
+
+    gen_helper_inb(data, cpu_env, port);
+    tcg_gen_ori_tl(data, data, 1 << a->bit);
+    gen_helper_outb(cpu_env, port, data);
+
+    tcg_temp_free_i32(port);
+    tcg_temp_free_i32(data);
+
+    return true;
+}
+
+/*
+ *  Clears a specified bit in an I/O Register. This instruction operates on
+ *  the lower 32 I/O Registers -- addresses 0-31.
+ */
+static bool trans_CBI(DisasContext *ctx, arg_CBI *a)
+{
+    TCGv data = tcg_temp_new_i32();
+    TCGv port = tcg_const_i32(a->reg);
+
+    gen_helper_inb(data, cpu_env, port);
+    tcg_gen_andi_tl(data, data, ~(1 << a->bit));
+    gen_helper_outb(cpu_env, port, data);
+
+    tcg_temp_free_i32(data);
+    tcg_temp_free_i32(port);
+
+    return true;
+}
+
+/*
+ *  Stores bit b from Rd to the T Flag in SREG (Status Register).
+ */
+static bool trans_BST(DisasContext *ctx, arg_BST *a)
+{
+    TCGv Rd = cpu_r[a->rd];
+
+    tcg_gen_andi_tl(cpu_Tf, Rd, 1 << a->bit);
+    tcg_gen_shri_tl(cpu_Tf, cpu_Tf, a->bit);
+
+    return true;
+}
+
+/*
+ *  Copies the T Flag in the SREG (Status Register) to bit b in register Rd.
+ */
+static bool trans_BLD(DisasContext *ctx, arg_BLD *a)
+{
+    TCGv Rd = cpu_r[a->rd];
+    TCGv t1 = tcg_temp_new_i32();
+
+    tcg_gen_andi_tl(Rd, Rd, ~(1u << a->bit)); /* clear bit */
+    tcg_gen_shli_tl(t1, cpu_Tf, a->bit); /* create mask */
+    tcg_gen_or_tl(Rd, Rd, t1);
+
+    tcg_temp_free_i32(t1);
+
+    return true;
+}
+
+/*
+ *  Sets a single Flag or bit in SREG.
+ */
+static bool trans_BSET(DisasContext *ctx, arg_BSET *a)
+{
+    switch (a->bit) {
+    case 0x00:
+        tcg_gen_movi_tl(cpu_Cf, 0x01);
+        break;
+    case 0x01:
+        tcg_gen_movi_tl(cpu_Zf, 0x01);
+        break;
+    case 0x02:
+        tcg_gen_movi_tl(cpu_Nf, 0x01);
+        break;
+    case 0x03:
+        tcg_gen_movi_tl(cpu_Vf, 0x01);
+        break;
+    case 0x04:
+        tcg_gen_movi_tl(cpu_Sf, 0x01);
+        break;
+    case 0x05:
+        tcg_gen_movi_tl(cpu_Hf, 0x01);
+        break;
+    case 0x06:
+        tcg_gen_movi_tl(cpu_Tf, 0x01);
+        break;
+    case 0x07:
+        tcg_gen_movi_tl(cpu_If, 0x01);
+        break;
+    }
+
+    return true;
+}
+
+/*
+ *  Clears a single Flag in SREG.
+ */
+static bool trans_BCLR(DisasContext *ctx, arg_BCLR *a)
+{
+    switch (a->bit) {
+    case 0x00:
+        tcg_gen_movi_tl(cpu_Cf, 0x00);
+        break;
+    case 0x01:
+        tcg_gen_movi_tl(cpu_Zf, 0x00);
+        break;
+    case 0x02:
+        tcg_gen_movi_tl(cpu_Nf, 0x00);
+        break;
+    case 0x03:
+        tcg_gen_movi_tl(cpu_Vf, 0x00);
+        break;
+    case 0x04:
+        tcg_gen_movi_tl(cpu_Sf, 0x00);
+        break;
+    case 0x05:
+        tcg_gen_movi_tl(cpu_Hf, 0x00);
+        break;
+    case 0x06:
+        tcg_gen_movi_tl(cpu_Tf, 0x00);
+        break;
+    case 0x07:
+        tcg_gen_movi_tl(cpu_If, 0x00);
+        break;
+    }
+
+    return true;
+}
-- 
2.17.2 (Apple Git-113)