From 9d4da737ffd282b01c8c0ea9bf33f8b497aa619b Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Fri, 21 Sep 2018 10:14:50 -0400
Subject: [PATCH] libbase/crt0-lm32.S: Add provisions for loading .data from
 flash.

:100644 100644 e0cd7153 34428845 M	litex/soc/software/libbase/crt0-lm32.S
---
 litex/soc/software/libbase/Makefile    |  7 +++++--
 litex/soc/software/libbase/crt0-lm32.S | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/litex/soc/software/libbase/Makefile b/litex/soc/software/libbase/Makefile
index b7f7d4cb..bf876204 100644
--- a/litex/soc/software/libbase/Makefile
+++ b/litex/soc/software/libbase/Makefile
@@ -4,7 +4,7 @@ include $(SOC_DIRECTORY)/software/common.mak
 OBJECTS=exception.o libc.o errno.o crc16.o crc32.o console.o \
 	system.o id.o uart.o time.o qsort.o strtod.o spiflash.o strcasecmp.o
 
-all: crt0-$(CPU).o libbase.a libbase-nofloat.a
+all: crt0-$(CPU).o crt0-$(CPU)-flash.o libbase.a libbase-nofloat.a
 
 libbase.a: $(OBJECTS) vsnprintf.o
 	$(AR) crs libbase.a $(OBJECTS) vsnprintf.o
@@ -24,8 +24,11 @@ vsnprintf-nofloat.o: $(LIBBASE_DIRECTORY)/vsnprintf.c
 %.o: $(LIBBASE_DIRECTORY)/%.S
 	$(assemble)
 
+crt0-$(CPU)-flash.o: $(LIBBASE_DIRECTORY)/crt0-$(CPU).S
+	$(CC) -c -DFLASH_DATA_SECTION $(CFLAGS) -o $@ $<
+
 .PHONY: all clean
 
 clean:
-	$(RM) $(OBJECTS) crt0-$(CPU).o vsnprintf.o vsnprintf-nofloat.o
+	$(RM) $(OBJECTS) crt0-$(CPU).o crt0-$(CPU)-flash.o vsnprintf.o vsnprintf-nofloat.o
 	$(RM) libbase.a libbase-nofloat.a .*~ *~
diff --git a/litex/soc/software/libbase/crt0-lm32.S b/litex/soc/software/libbase/crt0-lm32.S
index e0cd7153..3b65ba9f 100644
--- a/litex/soc/software/libbase/crt0-lm32.S
+++ b/litex/soc/software/libbase/crt0-lm32.S
@@ -112,6 +112,25 @@ _crt0:
 	mvhi    sp, hi(_fstack)
 	ori     sp, sp, lo(_fstack)
 
+#ifdef FLASH_DATA_SECTION
+	/* Load DATA */
+	mvhi    r1, hi(_erodata)
+	ori     r1, r1, lo(_erodata)
+	mvhi    r2, hi(_fdata)
+	ori     r2, r2, lo(_fdata)
+	mvhi    r3, hi(_edata)
+	ori     r3, r3, lo(_edata)
+.moveDATA:
+	be      r2, r3, .doBSS
+	lw      r4, (r1+0)
+	sw      (r2+0), r4
+	/* _edata is aligned to 16 bytes. Use word-xfers. */
+	addi    r1, r1, 4
+	addi    r2, r2, 4
+	bi     .moveDATA
+#endif
+
+.doBSS:
 	/* Clear BSS */
 	mvhi    r1, hi(_fbss)
 	ori     r1, r1, lo(_fbss)
-- 
2.30.2