From: Tobias Girstmair <tobi@isticktoit.net>
Date: Fri, 12 Mar 2021 18:42:27 +0000 (+0100)
Subject: add cycle count and some comments
X-Git-Url: https://git.gir.st/Chiptunes-pms150c.git/commitdiff_plain/c8495413a3e982060a7df769f25365fb5c54caf2

add cycle count and some comments
---

diff --git a/bsv.S b/bsv.S
index 27c61b5..84370bd 100644
--- a/bsv.S
+++ b/bsv.S
@@ -13,6 +13,7 @@ tmp_hi: .ds 1  ; 0x16
 tmp_lo: .ds 1  ; 0x17
 pwm: .ds 1     ; 0x18
 .area SSEG
+.even ; SP must be aligned? (sdcc does it)
 stack: .ds 1
 
 ; aliases for memory locations:
@@ -23,12 +24,17 @@ mul1 = tmp_lo
 mod3hi = tmp_hi
 mod3lo = tmp_lo
 
+; cycle count (worst-case)
+; mod3:    28
+; g:       81
+; sample: 115 + 4*g + 2*mod3 = 495
 
 
 .area CSEG (CODE,ABS)
 ;.area HOME
 ;.area HEADER (ABS)
 .org 0x0000
+	;TODO: 0x0000 must be NOP for autocalib routine
 	;TODO: move some init stuff here (space for 15 instr.)
 	GOTO	init
 
@@ -160,6 +166,11 @@ g:
 	RET
 
 init:
+	; AUTO_INIT_SYSCLOCK() -- 4mhz
+	; AUTO_CALIBRATE_SYSCLOCK() -- move away w/ goto
+	; ??: setup fuses (romlocation 0x3ff)
+	; setup SP (&= 0xfe)
+	; setup timer2, timer16
 	CLEAR	i0
 	CLEAR	i1
 	CLEAR	i2