From b6e716ddc51cf1bd7b30ead2c98ef6ef3bf9877b Mon Sep 17 00:00:00 2001
From: Sergiusz Bazanski <q3k@q3k.org>
Date: Sat, 27 Jul 2019 15:09:02 +0200
Subject: [PATCH] l0dables/lib: implement stdout and heap via newlib
---
l0dables/lib/hardware.c | 38 ++++++++++++++++++++++++++++++++++++++
l0dables/lib/l0dable.ld | 3 +++
l0dables/lib/meson.build | 2 +-
3 files changed, 42 insertions(+), 1 deletion(-)
diff --git a/l0dables/lib/hardware.c b/l0dables/lib/hardware.c
index 7a481afac..e9325a1c6 100644
--- a/l0dables/lib/hardware.c
+++ b/l0dables/lib/hardware.c
@@ -9,6 +9,9 @@
* initialization before main() gets called.
*/
+#include <stddef.h>
+#include "epicardium.h"
+
#include "max32665.h"
#include "mxc_sys.h"
#include "gcr_regs.h"
@@ -72,3 +75,38 @@ __weak void SystemInit() {
SystemCoreClockUpdate();
}
+
+// newlib syscall to allow printf to work.
+long _write(int fd, const char *buf, size_t cnt)
+{
+ /*
+ * Only print one line at a time. Insert `\r` between lines so
+ * they are properly displayed on the serial console.
+ */
+ size_t i, last = 0;
+ for (i = 0; i < cnt; i++) {
+ if (buf[i] == '\n') {
+ epic_uart_write_str(&buf[last], i - last);
+ epic_uart_write_str("\r", 1);
+ last = i;
+ }
+ }
+ if (last != i) {
+ epic_uart_write_str(&buf[last], cnt - last);
+ }
+ return cnt;
+}
+
+// newlib syscall to allow for a heap
+extern uint32_t __heap_start;
+uint32_t _sbrk(int incr)
+{
+ static char *brk = NULL;
+ if (brk == NULL) {
+ brk = (char *)&__heap_start;
+ }
+
+ char *prev_brk = brk;
+ brk += incr;
+ return (uint32_t)prev_brk;
+}
diff --git a/l0dables/lib/l0dable.ld b/l0dables/lib/l0dable.ld
index c1c392153..25f1a818b 100644
--- a/l0dables/lib/l0dable.ld
+++ b/l0dables/lib/l0dable.ld
@@ -71,6 +71,9 @@ SECTIONS {
*(COMMON)
} :data
+ /* Used by hardware.c as start of heap. */
+ __heap_start = .;
+
/* Limit based on current limitations of l0dable setup - only uses core1 RAM. */
ASSERT(. < 0x40000, "Exceeded available RAM")
diff --git a/l0dables/lib/meson.build b/l0dables/lib/meson.build
index c9d81c080..60d557d4e 100644
--- a/l0dables/lib/meson.build
+++ b/l0dables/lib/meson.build
@@ -2,7 +2,7 @@ l0dable_startup_lib = static_library(
'l0dable-startup',
'crt.s',
'hardware.c',
- dependencies: periphdriver,
+ dependencies: [periphdriver, api_caller],
pic: true,
)
--
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