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 total to 61 instructions plus NOP, 62 burned rows. The Dual-LUT nested Boolean family later expanded the live contract to 91 instructions plus NOP, 92 burned rows.
From the build
The work behind the words.
Conceptual FPGA HDMI illustration · MASKADD only; not proof of all nine new instructions.