From: Martin Perner <martin@perner.cc>
Date: Sun, 19 Dec 2010 17:09:27 +0000 (+0100)
Subject: [bench] vm: merged pc with address to input
X-Git-Tag: bootrom_v1~57
X-Git-Url: http://wien.tomnetworks.com/gitweb/?p=calu.git;a=commitdiff_plain;h=39b3fc6ba58ab1ff1c7ed04bacc15c8fcc987950

[bench] vm: merged pc with address to input

the pc isn't any more kept seperated from the
address to the input => reduced instructions
---

diff --git a/8_benchs/src/vm.s b/8_benchs/src/vm.s
index 37a1ae7..c39a847 100644
--- a/8_benchs/src/vm.s
+++ b/8_benchs/src/vm.s
@@ -34,26 +34,23 @@ main:
 
 vm:
 	;r0 ... lut address (can be overwritten)
-	;r1 ... addr to input
-	;r2 ... pc
+	;r1 ... address to input, every byte is a new input
+	;       includes pc implicitly
 	;r3 ... effective stack address
-	;r4 ... effective input addr
 	;r5 ... input
 
-	;set pc to -1
-	ldis r2, 0xFFFF
+	;decrement address to input by 1
+	subi r1, r1, 1
 	;load base address of stack
 	ldil r3, stack@lo
 	ldih r3, stack@hi
 
 vm_default:	
 vm_loop:
-	;increment pc
-	addi r2, r2, 1
-	;generate effective input addr
-	add r4, r1, r2
+	;increment input address
+	addi r1, r1, 1
 	;load input
-	ldb r5, 0(r4)
+	ldb r5, 0(r1)
 	;we need to multiply input by 4 to get correct address offset
 	lls r0, r5, 2
 	;calc position in jumptable
@@ -176,29 +173,29 @@ vm_dup:
 ;73
 vm_imm:
 	;load new high byte
-	ldb r6, 4(r4)
+	ldb r6, 4(r1)
 	;shift high byte
 	lls r6, r6, 8
 	;load 2nd byte
-	ldb r7, 3(r4)
+	ldb r7, 3(r1)
 	;add to high byte
 	add r6, r6, r7
 	;shift
 	lls r6, r6, 8
 	;load
-	ldb r7, 2(r4)
+	ldb r7, 2(r1)
 	;add
 	add r6, r6, r7
 	;shift
 	lls r6, r6, 8
 	;load
-	ldb r7, 1(r4)
+	ldb r7, 1(r1)
 	;add
 	add r6, r6, r7
 	;store result to stack
 	stw r6, 0(r3)
 	;pc+4
-	addi r2, r2, 4
+	addi r1, r1, 4
 	;increment sp
 	addi r3, r3, 4
 	br+ vm_loop
@@ -213,13 +210,13 @@ vm_jmp:
 	;compare to 0
 	cmpi r6,0
 	;increment pc if == 0
-	addideq r2, r2, 1
+	addideq r1, r1, 1
 	breq+ vm_loop
 	;if != 0
 	;set r6 to 0 (to clear upper bytes)
 	ldis r6, 0
 	;load pc+1 input
-	ldb r6, 1(r4)
+	ldb r6, 1(r1)
 	;compare input with neg. max of 8 bit
 	cmpi r6, 0x80
 	brlt- vm_possign
@@ -227,7 +224,7 @@ vm_jmp:
 	add r6, r6, r7
 vm_possign:
 	;pc += data
-	add r2, r2, r6
+	add r1, r1, r6
 	br+ vm_loop
 
 ;case P