--- a/target-utils/simagent/Makefile	Fri Mar 12 22:08:07 2021 +0000
+++ b/target-utils/simagent/Makefile	Fri Mar 12 23:36:46 2021 +0000
@@ -7,7 +7,7 @@
 INSTDIR=/opt/freecalypso/target-bin
 
 PROG=	simagent
-OBJS=	crt0.o byterx.o cmdtab.o invtable.o main.o simup.o
+OBJS=	crt0.o byterx.o cmdtab.o invtable.o main.o simup.o stringarg.o tx.o
 LIBS=	../libcommon/libcommon.a ../libprintf/libprintf.a ../libbase/libbase.a \
 	../libc/libc.a
 LIBGCC=	`${CC} -print-file-name=libgcc.a`

--- a/target-utils/simagent/cmdtab.c	Fri Mar 12 22:08:07 2021 +0000
+++ b/target-utils/simagent/cmdtab.c	Fri Mar 12 23:36:46 2021 +0000
@@ -9,6 +9,7 @@
 extern void cmd_r32();
 extern void cmd_sertimeout();
 extern void cmd_sim_up();
+extern void cmd_tx();
 extern void cmd_w8();
 extern void cmd_w16();
 extern void cmd_w32();
@@ -32,6 +33,7 @@
 	{"r32", cmd_r32},
 	{"sertimeout", cmd_sertimeout},
 	{"sim-up", cmd_sim_up},
+	{"tx", cmd_tx},
 	{"w8", cmd_w8},
 	{"w16", cmd_w16},
 	{"w32", cmd_w32},

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/target-utils/simagent/stringarg.c	Fri Mar 12 23:36:46 2021 +0000
@@ -0,0 +1,43 @@
+/*
+ * This module contains the function that parses our hex string arguments.
+ */
+
+#include <ctype.h>
+#include "types.h"
+
+static
+decode_hex_digit(c)
+{
+	if (isdigit(c))
+		return c - '0';
+	else if (islower(c))
+		return c - 'a' + 10;
+	else
+		return c - 'A' + 10;
+}
+
+decode_hex_string_arg(arg, buf, maxlen)
+	char *arg;
+	u8 *buf;
+	unsigned maxlen;
+{
+	unsigned count;
+
+	for (count = 0; ; ) {
+		while (isspace(*arg))
+			arg++;
+		if (!*arg)
+			break;
+		if (!isxdigit(arg[0]) || !isxdigit(arg[1])) {
+			printf("ERROR: invalid hex string input\n");
+			return;
+		}
+		if (count >= maxlen) {
+			printf("ERROR: hex string input is too long\n");
+			return;
+		}
+		buf[count++] = (decode_hex_digit(arg[0]) << 4) |
+				decode_hex_digit(arg[1]);
+	}
+	return count;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/target-utils/simagent/tx.c	Fri Mar 12 23:36:46 2021 +0000
@@ -0,0 +1,49 @@
+/*
+ * This module implements transmission of bytes toward the SIM.
+ */
+
+#include "types.h"
+#include "simregs.h"
+
+extern u16 conf1_reg;
+
+send_to_sim(bytes, count)
+	u8 *bytes;
+	unsigned count;
+{
+	unsigned n, timeout;
+
+	SIMREGS.conf1 = conf1_reg |= SIM_CONF1_TXRX;
+	if (count == 1)
+		wait_ARM_cycles(372 * 4);	/* wait 1 etu */
+	for (n = 0; ; ) {
+		SIMREGS.dtx = bytes[n++];
+		if (n == count) {
+			SIMREGS.conf1 = conf1_reg &= ~SIM_CONF1_TXRX;
+			return(0);
+		}
+		for (timeout = 12000; timeout; timeout--)
+			if (SIMREGS.it & SIM_IT_ITTX)
+				break;
+		if (!timeout) {
+			printf("ERROR: SIM interface Tx timeout\n");
+			return(-1);
+		}
+	}
+}
+
+cmd_tx(argstr)
+	char *argstr;
+{
+	u8 bytes[5];
+	int rc;
+
+	rc = decode_hex_string_arg(argstr, bytes, sizeof bytes);
+	if (rc < 0)
+		return;
+	if (rc == 0) {
+		printf("ERROR: empty hex string argument\n");
+		return;
+	}
+	send_to_sim(bytes, rc);
+}