trs80m1: Naïve initial implementation of external buffer support

This is just to make it work. We need custom buffer to user copiers (fast ones)
to make this work usefully.

diff --git a/Kernel/platform-trs80m1/buffers.c b/Kernel/platform-trs80m1/buffers.c
new file mode 100644 (file)
index 0000000..d6fccbe
--- /dev/null
+++ b/Kernel/platform-trs80m1/buffers.c
@@ -0,0 +1,97 @@
+#include <kernel.h>
+#include <kdata.h>
+
+/*
+ *     Must live in CODE2
+ */
+
+void blktok(void *kaddr, struct blkbuf *buf, uint16_t off, uint16_t len)
+{
+    __builtin_memcpy(kaddr, buf->__bf_data + off, len);
+}
+
+void blkfromk(void *kaddr, struct blkbuf *buf, uint16_t off, uint16_t len)
+{
+    __builtin_memcpy(buf->__bf_data + off, kaddr, len);
+}
+
+/*
+ *     Slow crap implementation purely for testing. We need to go direct
+ *     between bank 2 and user
+ */
+static uint8_t scratch2[512];
+void blktou(void *uaddr, struct blkbuf *buf, uint16_t off, uint16_t len)
+{
+    __builtin_memcpy(scratch2, buf->__bf_data + off, len);
+    uput(scratch2, uaddr, len);
+}
+
+void blkfromu(void *uaddr, struct blkbuf *buf, uint16_t off, uint16_t len)
+{
+    uget(uaddr, scratch2, len);
+    __builtin_memcpy(buf->__bf_data + off, scratch2, len);
+}
+
+static uint8_t scratchbuf[64];
+
+/* Worst case is needing to copy over about 64 bytes */
+void *blkptr(struct blkbuf *buf, uint16_t offset, uint16_t len)
+{
+    if (len > 64)
+        panic("blkptr");
+    __builtin_memcpy(scratchbuf, buf->__bf_data + offset, len);
+    return scratchbuf;
+}
+
+void blkzero(struct blkbuf *buf)
+{
+    __builtin_memset(buf->__bf_data, 0, BLKSIZE);
+}
+
+extern uint8_t bufdata[];
+
+void bufsetup(void)
+{
+    uint8_t *p = bufdata;
+    bufptr bp = bufpool;
+
+    for(bp = bufpool; bp < bufpool_end; ++bp) {
+        bp->__bf_data = p;
+        p += BLKSIZE;
+    }
+}
+
+
+/*
+ *     Scratch buffers for syscall arguments - until we can rework
+ *     execve and realloc to avoid this need
+ */
+
+static uint8_t tmp[2][BLKSIZE];
+static uint8_t tfree = 3;
+
+void tmpfree(void *p)
+{
+  if (p == tmp[0]) {
+      tfree |= 1;
+      return;
+  }
+  if (p == tmp[1]) {
+      tfree |= 2;
+      return;
+  }
+  panic("tmpfree");
+}
+
+void *tmpbuf(void)
+{
+   if (tfree & 1) {
+       tfree &= ~1;
+       return tmp[0];
+   }
+   if (tfree & 2) {
+       tfree &= ~2;
+       return tmp[1];
+   }
+   panic("tmpbuf");
+}