zeldin

This is a comparison between an AVR softcore and the picorv32 when used in a real application. The numbers are for the entire application, not for the cores in isolation. Only minimal changes were made to the HDL and firmware code to adapt to the new core (the peripherals were updated to handle a 32-bit bus, and the interrupt handling was adapted to picorv32, otherwise the code is identical) and the same optimization flags (-Os -mrelax) were used with both cores.

The following were the relevant design constraints:

• Synthetizable on an iCE40 HX8K
• fCPU = 17 MHz

zeldin

diff --git a/src/cmd/link/internal/ld/config.go b/src/cmd/link/internal/ld/config.go
index 60b6491859..2d8f96408e 100644
--- a/src/cmd/link/internal/ld/config.go
+++ b/src/cmd/link/internal/ld/config.go
@@ -247,9 +247,6 @@ func determineLinkMode(ctxt *Link) {
                        }
                        ctxt.LinkMode = LinkInternal
                case "1":
-                       if objabi.GOARCH == "ppc64" {
-                               Exitf("external linking requested via GO_EXTLINK_ENABLED but not supported for %s/ppc64", objabi.GOOS)

zeldin

# compile with:	 gcc -m32 -static -nostdlib -o hello hello.s

	
	.text

	.globl	_start

_start:	
	bl	1f
1:

zeldin

FW upload starts with a packet of type 8:

byte 0 : 00
byte 1 : 08 = FW upload start command
byte 2 : 03 = packet sequence number
byte 3 : 01 = upload protocol version?  Must be 1
byte 4-5 : 00 00 = total number of bytes (16-bit little endian), 0 means 64K (max size)
byte 6-7 : 7e 04 = total number of data blocks (16-bit little endian)
byte 8-9 : 00 00 = ? (not used)
byte 10: 39 = bytes of flash data per data block (decimal: 57) (not used)