hw: Clean up the bootrom

hw/system/spatz_cluster/test/bootrom.S

@@ -9,9 +9,41 @@
   .global BOOTDATA
 
 _start:
+  // Clear integer registers
+  mv x1, x0
+  mv x2, x0
+  mv x3, x0
+  mv x4, x0
+  mv x5, x0
+  mv x6, x0
+  mv x7, x0
+  mv x8, x0
+  mv x9, x0
+  mv x10, x0
+  mv x11, x0
+  mv x12, x0
+  mv x13, x0
+  mv x14, x0
+  mv x15, x0
+  mv x16, x0
+  mv x17, x0
+  mv x18, x0
+  mv x19, x0
+  mv x20, x0
+  mv x21, x0
+  mv x22, x0
+  mv x23, x0
+  mv x24, x0
+  mv x25, x0
+  mv x26, x0
+  mv x27, x0
+  mv x28, x0
+  mv x29, x0
+  mv x30, x0
+  mv x31, x0
+
   la      t1, exception
   csrw    mtvec, t1
-  csrr    a0, mhartid
   la      a1, BOOTDATA
 
   // Activate MEIP

hw/system/spatz_cluster/test/bootrom.dump

@@ -5,56 +5,83 @@ test/bootrom.elf:     file format elf32-littleriscv
 Disassembly of section .text:
 
 00001000 <_start>:
-    1000:	00000317          	auipc	t1,0x0
-    1004:	04430313          	addi	t1,t1,68 # 1044 <exception>
-    1008:	30531073          	csrw	mtvec,t1
-    100c:	f1402573          	csrr	a0,mhartid
-    1010:	00000597          	auipc	a1,0x0
-    1014:	04058593          	addi	a1,a1,64 # 1050 <BOOTDATA>
-    1018:	00001337          	lui	t1,0x1
-    101c:	80030313          	addi	t1,t1,-2048 # 800 <_start-0x800>
-    1020:	30431073          	csrw	0x304,t1
-    1024:	10500073          	wfi
-    1028:	0185a383          	lw	t2,24(a1)
-    102c:	0205ae03          	lw	t3,32(a1)
-    1030:	01c383b3          	add	t2,t2,t3
-    1034:	05838393          	addi	t2,t2,88
-    1038:	00038393          	mv	t2,t2
-    103c:	0003a383          	lw	t2,0(t2)
-    1040:	00038067          	jr	t2
+    1000:	00000093          	li	ra,0
+    1004:	00000113          	li	sp,0
+    1008:	00000193          	li	gp,0
+    100c:	00000213          	li	tp,0
+    1010:	00000293          	li	t0,0
+    1014:	00000313          	li	t1,0
+    1018:	00000393          	li	t2,0
+    101c:	00000413          	li	s0,0
+    1020:	00000493          	li	s1,0
+    1024:	00000513          	li	a0,0
+    1028:	00000593          	li	a1,0
+    102c:	00000613          	li	a2,0
+    1030:	00000693          	li	a3,0
+    1034:	00000713          	li	a4,0
+    1038:	00000793          	li	a5,0
+    103c:	00000813          	li	a6,0
+    1040:	00000893          	li	a7,0
+    1044:	00000913          	li	s2,0
+    1048:	00000993          	li	s3,0
+    104c:	00000a13          	li	s4,0
+    1050:	00000a93          	li	s5,0
+    1054:	00000b13          	li	s6,0
+    1058:	00000b93          	li	s7,0
+    105c:	00000c13          	li	s8,0
+    1060:	00000c93          	li	s9,0
+    1064:	00000d13          	li	s10,0
+    1068:	00000d93          	li	s11,0
+    106c:	00000e13          	li	t3,0
+    1070:	00000e93          	li	t4,0
+    1074:	00000f13          	li	t5,0
+    1078:	00000f93          	li	t6,0
+    107c:	00000317          	auipc	t1,0x0
+    1080:	04030313          	addi	t1,t1,64 # 10bc <exception>
+    1084:	30531073          	csrw	mtvec,t1
+    1088:	00000597          	auipc	a1,0x0
+    108c:	04058593          	addi	a1,a1,64 # 10c8 <BOOTDATA>
+    1090:	00001337          	lui	t1,0x1
+    1094:	80030313          	addi	t1,t1,-2048 # 800 <_start-0x800>
+    1098:	30431073          	csrw	0x304,t1
+    109c:	10500073          	wfi
+    10a0:	0185a383          	lw	t2,24(a1)
+    10a4:	0205ae03          	lw	t3,32(a1)
+    10a8:	01c383b3          	add	t2,t2,t3
+    10ac:	05838393          	addi	t2,t2,88
+    10b0:	00038393          	mv	t2,t2
+    10b4:	0003a383          	lw	t2,0(t2)
+    10b8:	00038067          	jr	t2
 
-00001044 <exception>:
-    1044:	10500073          	wfi
-    1048:	ffdff06f          	j	1044 <exception>
+000010bc <exception>:
+    10bc:	10500073          	wfi
+    10c0:	ffdff06f          	j	10bc <exception>
 
 Disassembly of section .rodata:
 
-00001050 <BOOTDATA>:
-    1050:	1000                	addi	s0,sp,32
-    1052:	0000                	unimp
-    1054:	0000                	unimp
-    1056:	0000                	unimp
-    1058:	0001                	nop
+000010c8 <BOOTDATA>:
+    10c8:	1000                	addi	s0,sp,32
+    10ca:	0000                	unimp
+    10cc:	0000                	unimp
+    10ce:	0000                	unimp
+    10d0:	0002                	0x2
 	...
-    106a:	0010                	addi	a2,sp,0
-    106c:	0000                	unimp
-    106e:	0000                	unimp
-    1070:	0000                	unimp
-    1072:	0002                	0x2
+    10e2:	0010                	addi	a2,sp,0
+    10e4:	0000                	unimp
+    10e6:	0000                	unimp
+    10e8:	0000                	unimp
+    10ea:	0002                	0x2
 	...
-    1080:	0000                	unimp
-    1082:	2000                	fld	fs0,0(s0)
-    1084:	0000                	unimp
-    1086:	0000                	unimp
-    1088:	0000                	unimp
-    108a:	2004                	fld	fs1,0(s0)
-    108c:	0000                	unimp
+    10f8:	0000                	unimp
+    10fa:	8000                	0x8000
+	...
+    1104:	0001                	nop
 	...
 
 Disassembly of section .boot_section:
 
-00001090 <entry_addr>:
-    1090:	1044                	addi	s1,sp,36
+00001108 <entry_addr>:
+    1108:	10bc                	addi	a5,sp,104
 	...
 
 Disassembly of section .Pulp_Chip.Info:
@@ -71,7 +98,7 @@ Disassembly of section .Pulp_Chip.Info:
   10:	495f 666e 006f      	0x6f666e495f
   16:	70696863          	bltu	s2,t1,726 <_start-0x8da>
   1a:	6e3d                	lui	t3,0xf
-  1c:	20656e6f          	jal	t3,56222 <entry_addr+0x55192>
+  1c:	20656e6f          	jal	t3,56222 <entry_addr+0x5511a>
   20:	3d757063          	bleu	s7,a0,3e0 <_start-0xc20>
   24:	6f6e                	flw	ft10,216(sp)
   26:	656e                	flw	fa0,216(sp)