OBD1 8bit High Cam RPM

This formula is used to convert values in the high cam table scales to real-world RPMs. If ''x'' is an 8-bit high-cam scale RPM value,

• Hi Cam RPM(''x'') = 1875000*''x'' / 53248

53248=D000h. Here is how it's calculated using standard integer fixed-point math tricks:

| |MOV er2, 0ach|; 0805 0 02 00 B5AC4A | |MOV er0, #0d000h|; 0808 0 02 00 449800D0 | |CLR A|; 080C 1 02 00 F9 | |DIV|; 080D 1 02 00 9037 | | |; DIV = (er0, A) <-- (er0, A) / er2; in this case, 0xd0000000 / (1875000/RPM) | | |; using bytes instead of words, (r1,r0,Ah,Al) <-- (r1,r0,Ah,Al) / (r5,r4) |||''... store the high bit of A, decide whether the divide overflowed, etc...'' | |LB A, r0|; 0817 0 02 00 78 | | |;r0 is the least significant byte of er0, which is the most significant word of the quotient! | |JNE label_081f|; 0818 0 02 00 CE05 |||''... overflow conditions, etc...'' |label_081f:|STB A, 0aah|; 081F 0 02 00 D5AA