Dispatch · ISA
ISA Upgrade: Nine New Tricks
Nine new instruction names exposed work the Dual-LUT datapath could already perform.
Historical entry: this page records the project at the time. Current facts and execution labels follow the status page.
Two days after writing that assembly language was hiding part of the machine, I added names for nine operations the hardware could already perform: ANDN, ORN, CSEL, ANDADD, ORADD, XORADD, ADC, SBC, and RSB.
One row in docs/isa/tomato.v1.csv gives each operation a burned control row. Directed simulation caught an incorrect reverse-subtract mapping before it could become part of the image, and software/asm/p0p1.s exercises all nine.
This dated entry records the change that brought the current total to 61 instructions plus NOP, 62 burned rows.
From the build
The work behind the words.
Conceptual FPGA HDMI illustration · MASKADD only; not proof of all nine new instructions.