target-ppc: Implement bcdcfn. instruction

bcdcfn. converts from National numeric format to BCD. National format
uses a byte to represent a digit where the most significant nibble is
always 0x3 and the least sign. nibbles is the digit itself.

Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

target-ppc/helper.h

@@ -378,6 +378,7 @@ DEF_HELPER_4(vpermxor, void, avr, avr, avr, avr)
 
 DEF_HELPER_4(bcdadd, i32, avr, avr, avr, i32)
 DEF_HELPER_4(bcdsub, i32, avr, avr, avr, i32)
+DEF_HELPER_3(bcdcfn, i32, avr, avr, i32)
 
 DEF_HELPER_2(xsadddp, void, env, i32)
 DEF_HELPER_2(xssubdp, void, env, i32)

target-ppc/int_helper.c

@@ -2492,6 +2492,8 @@ void helper_vsubecuq(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c)
 #define BCD_NEG_PREF    0xD
 #define BCD_NEG_ALT     0xB
 #define BCD_PLUS_ALT_2  0xE
+#define NATIONAL_PLUS   0x2B
+#define NATIONAL_NEG    0x2D
 
 #if defined(HOST_WORDS_BIGENDIAN)
 #define BCD_DIG_BYTE(n) (15 - (n/2))
@@ -2558,6 +2560,24 @@ static void bcd_put_digit(ppc_avr_t *bcd, uint8_t digit, int n)
     }
 }
 
+static int bcd_cmp_zero(ppc_avr_t *bcd)
+{
+    if (bcd->u64[HI_IDX] == 0 && (bcd->u64[LO_IDX] >> 4) == 0) {
+        return 1 << CRF_EQ;
+    } else {
+        return (bcd_get_sgn(bcd) == 1) ? 1 << CRF_GT : 1 << CRF_LT;
+    }
+}
+
+static uint16_t get_national_digit(ppc_avr_t *reg, int n)
+{
+#if defined(HOST_WORDS_BIGENDIAN)
+    return reg->u16[8 - n];
+#else
+    return reg->u16[n];
+#endif
+}
+
 static int bcd_cmp_mag(ppc_avr_t *a, ppc_avr_t *b)
 {
     int i;
@@ -2688,6 +2708,42 @@ uint32_t helper_bcdsub(ppc_avr_t *r,  ppc_avr_t *a, ppc_avr_t *b, uint32_t ps)
     return helper_bcdadd(r, a, &bcopy, ps);
 }
 
+uint32_t helper_bcdcfn(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
+{
+    int i;
+    int cr = 0;
+    uint16_t national = 0;
+    uint16_t sgnb = get_national_digit(b, 0);
+    ppc_avr_t ret = { .u64 = { 0, 0 } };
+    int invalid = (sgnb != NATIONAL_PLUS && sgnb != NATIONAL_NEG);
+
+    for (i = 1; i < 8; i++) {
+        national = get_national_digit(b, i);
+        if (unlikely(national < 0x30 || national > 0x39)) {
+            invalid = 1;
+            break;
+        }
+
+        bcd_put_digit(&ret, national & 0xf, i);
+    }
+
+    if (sgnb == NATIONAL_PLUS) {
+        bcd_put_digit(&ret, (ps == 0) ? BCD_PLUS_PREF_1 : BCD_PLUS_PREF_2, 0);
+    } else {
+        bcd_put_digit(&ret, BCD_NEG_PREF, 0);
+    }
+
+    cr = bcd_cmp_zero(&ret);
+
+    if (unlikely(invalid)) {
+        cr = 1 << CRF_SO;
+    }
+
+    *r = ret;
+
+    return cr;
+}
+
 void helper_vsbox(ppc_avr_t *r, ppc_avr_t *a)
 {
     int i;

target-ppc/translate/vmx-impl.inc.c

@@ -960,8 +960,61 @@ static void gen_##op(DisasContext *ctx)             \
     tcg_temp_free_i32(ps);                          \
 }
 
+#define GEN_BCD2(op)                                \
+static void gen_##op(DisasContext *ctx)             \
+{                                                   \
+    TCGv_ptr rd, rb;                                \
+    TCGv_i32 ps;                                    \
+                                                    \
+    if (unlikely(!ctx->altivec_enabled)) {          \
+        gen_exception(ctx, POWERPC_EXCP_VPU);       \
+        return;                                     \
+    }                                               \
+                                                    \
+    rb = gen_avr_ptr(rB(ctx->opcode));              \
+    rd = gen_avr_ptr(rD(ctx->opcode));              \
+                                                    \
+    ps = tcg_const_i32((ctx->opcode & 0x200) != 0); \
+                                                    \
+    gen_helper_##op(cpu_crf[6], rd, rb, ps);        \
+                                                    \
+    tcg_temp_free_ptr(rb);                          \
+    tcg_temp_free_ptr(rd);                          \
+    tcg_temp_free_i32(ps);                          \
+}
+
 GEN_BCD(bcdadd)
 GEN_BCD(bcdsub)
+GEN_BCD2(bcdcfn)
+
+static void gen_xpnd04_1(DisasContext *ctx)
+{
+    switch (opc4(ctx->opcode)) {
+    case 7:
+        gen_bcdcfn(ctx);
+        break;
+    default:
+        gen_invalid(ctx);
+        break;
+    }
+}
+
+static void gen_xpnd04_2(DisasContext *ctx)
+{
+    switch (opc4(ctx->opcode)) {
+    case 7:
+        gen_bcdcfn(ctx);
+        break;
+    default:
+        gen_invalid(ctx);
+        break;
+    }
+}
+
+GEN_VXFORM_DUAL(vsubcuw, PPC_ALTIVEC, PPC_NONE, \
+                xpnd04_1, PPC_NONE, PPC2_ISA300)
+GEN_VXFORM_DUAL(vsubsws, PPC_ALTIVEC, PPC_NONE, \
+                xpnd04_2, PPC_NONE, PPC2_ISA300)
 
 GEN_VXFORM_DUAL(vsububm, PPC_ALTIVEC, PPC_NONE, \
                 bcdadd, PPC_NONE, PPC2_ALTIVEC_207)
@@ -1038,3 +1091,5 @@ GEN_VXFORM_DUAL(vsldoi, PPC_ALTIVEC, PPC_NONE,
 #undef GEN_VXFORM_NOA
 #undef GEN_VXFORM_UIMM
 #undef GEN_VAFORM_PAIRED
+
+#undef GEN_BCD2

target-ppc/translate/vmx-ops.inc.c

@@ -126,7 +126,7 @@ GEN_HANDLER_E_2(vprtybw, 0x4, 0x1, 0x18, 8, 0, PPC_NONE, PPC2_ISA300),
 GEN_HANDLER_E_2(vprtybd, 0x4, 0x1, 0x18, 9, 0, PPC_NONE, PPC2_ISA300),
 GEN_HANDLER_E_2(vprtybq, 0x4, 0x1, 0x18, 10, 0, PPC_NONE, PPC2_ISA300),
 
-GEN_VXFORM(vsubcuw, 0, 22),
+GEN_VXFORM_DUAL(vsubcuw, xpnd04_1, 0, 22, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM_DUAL(vaddubs, vmul10uq, 0, 8, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM_DUAL(vadduhs, vmul10euq, 0, 9, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM(vadduws, 0, 10),
@@ -138,7 +138,7 @@ GEN_VXFORM_DUAL(vsubuhs, bcdsub, 0, 25, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM(vsubuws, 0, 26),
 GEN_VXFORM(vsubsbs, 0, 28),
 GEN_VXFORM(vsubshs, 0, 29),
-GEN_VXFORM(vsubsws, 0, 30),
+GEN_VXFORM_DUAL(vsubsws, xpnd04_2, 0, 30, PPC_ALTIVEC, PPC_NONE),
 GEN_VXFORM_207(vadduqm, 0, 4),
 GEN_VXFORM_207(vaddcuq, 0, 5),
 GEN_VXFORM_DUAL(vaddeuqm, vaddecuq, 30, 0xFF, PPC_NONE, PPC2_ALTIVEC_207),