target/s390x: Emulate CVB, CVBY and CVBG

Convert to Binary - counterparts of the already implemented Convert
to Decimal (CVD*) instructions.
Example from the Principles of Operation: 25594C becomes 63FA.

Co-developed-by: Pavel Zbitskiy <pavel.zbitskiy@gmail.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240205205830.6425-3-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

target/s390x/helper.h

@@ -88,6 +88,8 @@ DEF_HELPER_FLAGS_3(tcxb, TCG_CALL_NO_RWG_SE, i32, env, i128, i64)
 DEF_HELPER_FLAGS_2(sqeb, TCG_CALL_NO_WG, i64, env, i64)
 DEF_HELPER_FLAGS_2(sqdb, TCG_CALL_NO_WG, i64, env, i64)
 DEF_HELPER_FLAGS_2(sqxb, TCG_CALL_NO_WG, i128, env, i128)
+DEF_HELPER_3(cvb, void, env, i32, i64)
+DEF_HELPER_FLAGS_2(cvbg, TCG_CALL_NO_WG, i64, env, i128)
 DEF_HELPER_FLAGS_1(cvd, TCG_CALL_NO_RWG_SE, i64, s32)
 DEF_HELPER_FLAGS_1(cvdg, TCG_CALL_NO_RWG_SE, i128, s64)
 DEF_HELPER_FLAGS_4(pack, TCG_CALL_NO_WG, void, env, i32, i64, i64)

target/s390x/tcg/insn-data.h.inc

@@ -293,6 +293,10 @@
     D(0xec73, CLFIT,   RIE_a, GIE, r1_32u, i2_16u, 0, 0, ct, 0, 1)
     D(0xec71, CLGIT,   RIE_a, GIE, r1_o, i2_16u, 0, 0, ct, 0, 1)
 
+/* CONVERT TO BINARY */
+    C(0x4f00, CVB,     RX_a,  Z,   la2, 0, 0, 0, cvb, 0)
+    C(0xe306, CVBY,    RXY_a, LD,  la2, 0, 0, 0, cvb, 0)
+    C(0xe30e, CVBG,    RXY_a, Z,   la2, 0, r1, 0, cvbg, 0)
 /* CONVERT TO DECIMAL */
     C(0x4e00, CVD,     RX_a,  Z,   r1_o, a2, 0, 0, cvd, 0)
     C(0xe326, CVDY,    RXY_a, LD,  r1_o, a2, 0, 0, cvd, 0)

target/s390x/tcg/int_helper.c

@@ -25,6 +25,7 @@
 #include "exec/exec-all.h"
 #include "qemu/host-utils.h"
 #include "exec/helper-proto.h"
+#include "exec/cpu_ldst.h"
 
 /* #define DEBUG_HELPER */
 #ifdef DEBUG_HELPER
@@ -98,6 +99,81 @@ Int128 HELPER(divu64)(CPUS390XState *env, uint64_t ah, uint64_t al, uint64_t b)
     tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
 }
 
+void HELPER(cvb)(CPUS390XState *env, uint32_t r1, uint64_t dec)
+{
+    int64_t pow10 = 1, bin = 0;
+    int digit, sign;
+
+    sign = dec & 0xf;
+    if (sign < 0xa) {
+        tcg_s390_data_exception(env, 0, GETPC());
+    }
+    dec >>= 4;
+
+    while (dec) {
+        digit = dec & 0xf;
+        if (digit > 0x9) {
+            tcg_s390_data_exception(env, 0, GETPC());
+        }
+        dec >>= 4;
+        bin += digit * pow10;
+        pow10 *= 10;
+    }
+
+    if (sign == 0xb || sign == 0xd) {
+        bin = -bin;
+    }
+
+    /* R1 is updated even on fixed-point-divide exception. */
+    env->regs[r1] = (env->regs[r1] & 0xffffffff00000000ULL) | (uint32_t)bin;
+    if (bin != (int32_t)bin) {
+        tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
+    }
+}
+
+uint64_t HELPER(cvbg)(CPUS390XState *env, Int128 dec)
+{
+    uint64_t dec64[] = {int128_getlo(dec), int128_gethi(dec)};
+    int64_t bin = 0, pow10, tmp;
+    int digit, i, sign;
+
+    sign = dec64[0] & 0xf;
+    if (sign < 0xa) {
+        tcg_s390_data_exception(env, 0, GETPC());
+    }
+    dec64[0] >>= 4;
+    pow10 = (sign == 0xb || sign == 0xd) ? -1 : 1;
+
+    for (i = 1; i < 20; i++) {
+        digit = dec64[i >> 4] & 0xf;
+        if (digit > 0x9) {
+            tcg_s390_data_exception(env, 0, GETPC());
+        }
+        dec64[i >> 4] >>= 4;
+        /*
+         * Prepend the next digit and check for overflow. The multiplication
+         * cannot overflow, since, conveniently, the int64_t limits are
+         * approximately +-9.2E+18. If bin is zero, the addition cannot
+         * overflow. Otherwise bin is known to have the same sign as the rhs
+         * addend, in which case overflow happens if and only if the result
+         * has a different sign.
+         */
+        tmp = bin + pow10 * digit;
+        if (bin && ((tmp ^ bin) < 0)) {
+            tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
+        }
+        bin = tmp;
+        pow10 *= 10;
+    }
+
+    g_assert(!dec64[0]);
+    if (dec64[1]) {
+        tcg_s390_program_interrupt(env, PGM_FIXPT_DIVIDE, GETPC());
+    }
+
+    return bin;
+}
+
 uint64_t HELPER(cvd)(int32_t reg)
 {
     /* positive 0 */

target/s390x/tcg/translate.c

@@ -2223,6 +2223,22 @@ static DisasJumpType op_csp(DisasContext *s, DisasOps *o)
 }
 #endif
 
+static DisasJumpType op_cvb(DisasContext *s, DisasOps *o)
+{
+    TCGv_i64 t = tcg_temp_new_i64();
+    tcg_gen_qemu_ld_i64(t, o->addr1, get_mem_index(s), MO_TEUQ);
+    gen_helper_cvb(tcg_env, tcg_constant_i32(get_field(s, r1)), t);
+    return DISAS_NEXT;
+}
+
+static DisasJumpType op_cvbg(DisasContext *s, DisasOps *o)
+{
+    TCGv_i128 t = tcg_temp_new_i128();
+    tcg_gen_qemu_ld_i128(t, o->addr1, get_mem_index(s), MO_TE | MO_128);
+    gen_helper_cvbg(o->out, tcg_env, t);
+    return DISAS_NEXT;
+}
+
 static DisasJumpType op_cvd(DisasContext *s, DisasOps *o)
 {
     TCGv_i64 t1 = tcg_temp_new_i64();